1A Auto Video Library
Our how-to videos have helped repair over 100 million vehicles

How to Install Invidia Q300 Exhaust 11-16 Subaru WRX

Share on:
  1. step : Removing the Mufflers (0:31)
    • Remove the 14mm bolts from the muffler
    • Slide the muffler off of the hanger
  2. step : Removing the Mid-Pipe (3:20)
    • Remove the 12mm spring bolts from the mid-pipe
    • Lower the mid-pipe from the hanger with a helper
  3. step : Installing the Mid-Pipe (7:04)
    • Insert the gasket to the mid-pipe pieces and loosely tighten them
    • Hang the mid pipe into place
    • Attach an adaptor plate to the donut gasket on the cat-back exhaust
    • Attach the adaptor place to the mid pipe
  4. step : Installing the Mufflers (9:05)
    • Hang the muffler into place
    • Attach the gasket to the mid-pipe
    • Capture the bolts
    • Tighten the 12mm bolts with the gasket to the mid-pipe
    • Tighten the 16mm bolts with the gasket to the muffler

Hi, I’m Mike from 1A Auto. We’ve been selling auto parts for over 30 years!

We going to start removing the exhaust by taking the mufflers off. There is two mufflers on this car. I'll put a little rust penetrate oil on here. There aren't too rusty but it will help with bolts to come out. These are 14 Millimeter. Get that one free. It's a nut and a bolt. I'll get the other one free first. Now I've got it free. I'm going to use my ratcheting wrench. I'm going to hold the other side with the box wrench. Got the other one a little bit. This one is real loose now, so I'm going to take it off with my fingers. Push that out. Just going to put this nut on this bolt just so they stay together in case we need to reuse them.

Now, we need to slide this muffler off the hangers. There is a hanger here, and there is a hanger on the other side, up in the body. And you can see this muffler is pretty loose. So it's going to have to go forward first. Now, we going to go backwards and slide it off this way. You have to reach up in there and just help it along. You get a good grip on the muffler, so we don't want it to fall. Okay. I'm going to put some rust penetrate on these bolts. Break these free. These here are 14 millimeter. Break the one free.

If it's going to broke free, you can hold the both head with your box wrench. You can take a ratcheting wrench and do the nut. Got it loose now, so I can take it out by a finger. Check these nuts and bolts together. So this muffler also has a hanger on the outside and on the inside here. Going to take it off this rear one first. So as you push this rubber off here make sure you have a really grip on this muffler because it will drop and it can hit you in the face.

Next step is to remove these spring bolts. This would be your mid-pipe and this would be the part of your exhaust that has the catalytic converter in it. So from here back is the cat back. Use some rust penetrate oil on them. All right, so this spring bolts the reason why they're like that is to keep tension on this big donut gasket that's in here. And any flex in the exhaust helps keep that joint nice and tight. So this outside nuts are 12 millimeter. See if I can break them free first. All right, I'm going to have to counter hold that bolt, 14 millimeter and a 12. This one is free. There is just some rust on it. A little stiff.

Let's spray some more penetrate oil in there. Sometimes if you re-tighten them after you put rust penetrate in there it can help work it back and forth to help free the stuck bolt. We're going to reuse this gasket. This donut gasket because it still looks pretty good, so we're not going to touch it. We just leave it right where it is. We don't want to disturb it. So now this pipe is loose, it's got one single hanger I've already done it from the mufflers, so now we need to remove it from this hanger.

Okay, so to get this long pipe here. You’re going to want someone to help you with it. So you be on that end to hold to up and I'm going to work it off the hanger right here, and that way it doesn't swing down because it's probably going to need two hands to get off this hanger.

So over here we have the stock exhaust off our 2016 WRX, and over here we have the Invidia Cat Back. It's about three inches all the way through. We’re going to use a Grimmspeed gasket adapter kit at the Cat Back flange with that donut gasket. It comes with all the gaskets you need. Comes with the ones that go between here. Comes with the one to go between here. So now, if you notice, this is two pieces versus the full single piece of the factory. It's going to be a little bit easier to install because we don't have to wrestle with this big piece. What we're going to do is install it on the ground and then hang it. It's also got a flex section here.

So instead of using those spring bolts to get flex to this, your flex section is now going to be here. So just looking at this, the welds look really nice, very clean. The flanges are nice and flat and thick, they're welded on really nice. So this should seal up and not cause any leaks. Got this nice Titanium sort of burn look on the end of the tips, that's pretty cool looking as opposed to just the factory chrome covers. Yeah, we got this nice welded brass with Invidia in there.

So we're going to start by installing this. We're going to bolt these two pipes together just loosely with the gasket, so that we can go up to the car and just hang it because otherwise you've got no hanger on this exhaust pipe. We're going to have to wrestle with it under the car to hook it to the Cat Back part. So slide the gasket in there. Just a little closer. Bolt through. The other bolt through. So you can adjust it once it's on the car. So you want to leave them loose.

On this donut gasket, the exhaust is not actually going to butt to this flange. You can see this little rust ring here and then it's kind of blackish here, that's where the original exhaust was sitting. So using our adapter plate, it has a little chamfer in here, it's gonna sit just like this. And then we're going to put another gasket here. Our exhaust will butt up against this and we'll put through bolts to hold everything together. All right, so having someone help you, you can install this piece here. So it's actually going to come backwards. And get it up here on the hanger. Okay, that's in the hanger now.

You get our adapter. Our adapter plate up. Or exhaust gasket. You got to line up there. You might have to spin it a little bit. So if you can slide those bolts through trying to get through the gasket too. So just capture those nuts so they don't back out. Let's start with the driver side muffler first. You start a little bit of water displacement oil. Put on the hangers. So this oil will dry pretty quickly and it won't leave any residue. Here we go. Now keep the other hanger, so we have to go all the way forward just like that. Let's slide it backwards. All right, so we’re going to leave that loose like that for now. So, again, we're going to spray some water displacement oil on the exhaust hangers. This helps the muffler slide in there. Let's start with the back hanger. This is the front or the rear one and slide it in. So now the exhaust is hanging in there, the muffler. All right, so we're going to put the gasket on this side.

Now, I'm just putting these bolts in hand tight because the holes are slotted. We going to have to adjust just to make sure everything sits right. Now, we going to install the gasket on the passenger side. Bolt through. It's okay if the gasket falls down, you can just get the nut captured. The exhaust is pushed towards the passenger side. See it's pretty tight here, and it's pretty tight here, so we want to adjust in this direction.

I'm going to start by moving this hanger down here. Just spray some more water displacement oil on this hanger. Again, you remember everything, all the bolts are loose because we want to adjust the position of it. So these new bolts are 13 millimeter. I'm going to put a little bit of Copper Anti-seize on here. That way, if you ever take this exhaust off, it should be a little bit easier. So Copper Anti-seize is typically for exhaust. It's for high heat applications. So with someone helping you, you want to hold it up nice and square like that. Just slide this down. Get it fairly snug by using my hands. 13 millimeter box wrench and a 13 millimeter ratcheting wrench. Start one side, move to the other side. Just make sure that I'm sealing it down nice and square. You can see it sealing right where the original pipe met that gasket. You want to tighten down one side then move the other side a little bit. All right, that's nice and tight.

It's now working at this flange that's sort of in the middle of the mid-pipe that goes to this wide pipe. I'm going to add some Copper never seize. Okay, these are 14 millimeter bolts and nuts, so with your assistant helping, you we're going to get this position. To bring it this nice and position square it's useful having somebody helping you. Try to do it evenly both sides. Okay, that's tight. That's tight. Working on the passenger’s side again. I'm going to add some Copper Anti-seize to the bolt. Add to the other one. So these are also 14 millimeter. Get them lined up. Got to tighten them down evenly. These holes are slotted. Got to loosen these nuts, put some Copper never seize. All right, this one is pretty loose, I'm going to get it kind of in the right place and then I'll tighten it with my fingers.

So I'm not going forever with the wrenches. These are 14 millimeter box wrench, 14 millimeter ratchet. That one, done one. Now this exhaust is nice Titanium and we've been touching it with greasy hands and stuff and we don't want that to burn in on the finish. So I'm just going to take some glass cleaner just spray it on a paper towel or rag and just sort of try to wipe it down as best as I can. I know you're like, why is this guy going crazy wiping it down because it's going on the car but I want it to at least look nice for a little while.

The important part is cleaning the mufflers because you're going to see that, and with heat these might stain a bit. You will get like heat stains and especially this tips. There is some greasy fingerprints on here, and once these get hot, those greasy fingerprints can burn in there. So just taking some glass cleaner and just wiping them down just ensures that you'll keep this nice blue finish. And you don't want to get really aggressive when cleaning it, just enough to wipe it off because you can ruin this finish.

Thanks for watching. Visit us at for quality auto parts, fast and free shipping, and the best customer service in the industry.

Tools needed for replacement:

    Materials, Fluids, and Supplies

  • Rust Penetrant

  • Wrenches - Metric

  • 14mm Wrench
  • 16mm Wrench
  • 12mm Wrench

Search Videos
Go To Top

Same Day Shipping

Orders ship same day when ordered by 2pm ET. Need your part faster? Choose expedited shipping at checkout.

Guaranteed To Fit

Providing you the highest quality, direct fit replacement auto parts enforced to the strictest product standards.

USA Customer Support

Exceeding customers' expectations every day, our team of passionate auto enthusiasts are here to help.

Instructional Video Library

Thousands of how-to auto repair videos specific to year, make and model guide you step-by-step through your repair.