Today I installed an Invidia N1 Exhaust on my 09 WRX. I have created a step by step article to help you if you decide to do the same. Even though this was done on a Subaru, it is pretty much the same process no matter what car you do this on.
First things first, you will need to pull your old exhaust system. Spray all the hangers and nuts with penetrating oil. Aero Kroil or PB Blaster work well. I did not take pics of this process. It is really simple. Remove the nuts, and pop the hanger rods out of the rubber hangers. I stress the fact that the factory stamped heat shields are sharp. Wearing gloves during this install is definitely recommended.
So here is a picture of this beauty, fresh out of the box. Invidia did a really great job packaging this up. UPS beat the heck out of it, but it was wrapped with so much expansion foam, and the tip was so well protected, it was in perfect condition.
Now if you have a downpipe that uses spring bolts (Cobb) you will need to drill out the downpipe’s flanges. Get a 7/16ths bit and start drilling. Be careful to keep the holes centered. If you have an Invidia downpipe, or one that has flat flanges (not a donut gasket style) you can skip this step.
Now that your downpipe is ready to accept the correct hardware, you will want to test fit the midpipe and make sure that it fits correctly. The Invidia sticker faces the under side of the car. Make sure to insert the supplied gasket between the downpipe and midpipe flanges. Put the bolts that Invidia supplied in the holes, and attach the midpipe. Do not tighten the bolts more than a loose finger tight. You may need to make an adjustment later on.
Now that the midpipe is hanging there, get the axleback section. Be careful not to damage the canister or the tip. Even though it is a titanium tip, you don’t want your brand new exhaust to have a ding or scratch. Push the hanger rods into the rubber hangers. They should slide in easily, since they are still oily from removing the old exhaust.
Now that the axleback section is hanging loosely from the hangers, You will want to bolt it to the midpipe. Take the supplied gasket and insert it between the flanges of the midpipe and the axleback section. Using the supplied bolts, attach the two sections. Leave the bolts finger tight so you can make adjustments if necessary.
Take the additional hanger bracket, and slide through the unused hanger. Attach the bracket to the exhaust with the supplied bolt, and finger tighten. This will keep the muffler from hanging uneven.
Now you are almost finished. Starting at the downpipe, begin to tighten the bolts. Make sure that the flanges line up correctly. If they do not, give the pipe a little twist and since you left all the other nuts and bolts finger tight, it will line up with ease. Tighten the bolts until they are very tight, but keep an eye on the flanges. You do not want to over tighten and bow the flanges. This will cause an exhaust leak if you do so.
After those flanges are aligned and the bolts are tightened, move down to the connection between the midpipe and the axleback section. Align the flanges and tighten the bolts the same as you did for the downpipe connection. Remember you want them very tight, but do not over tighten and bow the flanges.
Move back to the hanger bracket and adjust as necessary to align the tip with the body. Make sure that the tip and the canister is not rubbing on the bumper. This will cause excessive in cabin noise, as well as potentially heat warping the bumper. After that is finished, double check all your connections to make sure they are tight.
You have finished. Now it is time to start it up and listen to the rumble. Here is a sound clip. Personally I love the sound. Just right as far as how loud it is, but has a really deep throaty growl.