Went to a reputable muffler shop the other day that a friend reccommended, they told me a 3" system might not work because of the space available at axel-kickover pipe, and a 3" pipe might be too close to the gas tank. They would however replace the old exhaust from turbo back with 3" stainless if possible or 2.5", eliminate the cat and install a nice magnaflow muffler with dual tips, making it look (almost) completely stock for $350. Also, yes the downpipe is 2.5", but after the cat, the pipes become 2.25" and as I mentioned just before the axel-kickover bottlenecks to a 1.875" as mentioned on "The TC Pages" (Yes, I was able to measure the pipes when my car was on the lift to confirm this).