I am getting ready to put on the GM Touring Catback exhaust system part#17802015 on my 07 H3. My question is that while I was under it the other day checking some things out I noticed that part of the factory pipe that is both directly in front and behind the converter seems to be somewhat "flattened". It looks like this was done at the factory and the only reason I can see that it was done was for extra clearance. Is this in fact the case and it comes from the factory that way? Also my new system would not replace that portion of the pipe so any suggestions on if I should see about possibly replacing it with a piece that is not flattened. It looks like that there would be enough room in this area where the pipe would not have to be that way but I just wanted to get the thought of others on the subject.

Thanks

 

The flat spots are from the factory like you said for clearance, you can go to a custom exhaust shop and the can bend up some new pipe for you.

 

This is all true, but be aware you still need more clearance than you might otherwise think because of flexing the truck off road, and making a round pipe oval does not reduce air flow. GM just went a bit overboard with it.

BTW if you think the I5 is bad, take a look at the Alpha stock Y pipe!