i have a stock 2002 180tt. Bought this turbo downpipe on ebay that fits stock180tt (http://i2.ebayimg.com/05/i/06/86/aa/3f_1.JPG). What i wan't to do is install the downpipe + cut off the stock muffler and put a magnaflow magnapack on in it's place. I need to find out the stock tubing size in order to buy the right muffler to weld on, is it 2" or 2.5"?

With the turbo downpipe and a straight thru muffler does that pretty much make a straight shot exhaust system or is there other stock resonators/cats that i need to get rid of?

 

Im pretty sure stock is 2.25

 

2.25 an there is a Cat involved as well. also, at least with the 225 HP, as the exhaust gets towards the back of the car there is a spot where the exhaust "pancakes" out, then goes back to round. The section I would say is about a foot long. If you are wanting to do a performance mod with the exhaust, instead of cutting and piecing odds and ends together, save the $$$ and get a complete 3 inch set up. APR makes a REALLY nice exaust from the turbo back. Its costly but its done right. Im saving for it currently.