Hello, I'm looking into going full 3 inch turbo back. currently running a 3 inch cat back. I have a 3 inch downpipe that I am waiting to put on, but it isn't as long as the stock one as it leaves out the cat or room for a test pipe. I'm thinking I wanna leave the main cat for legal reasons. I talked to an exhaust shop and they said they could cut up the main cat on the stock downpipe and make it work with my setup. Only thing is the stock cat is 2.5 inches. I'm just wondering whether or not I should use the stock cat or buy a high flow 3 inch. Since it will be slightly restricted at the cat is it worth it to spend another couple hundred bucks for a 3 inch cat? Or will the .5 inch restriction not make a huge difference? Please let me know what you guys think. Car is stock no boost controller or anything like that.