soooooooooooo far off the original topic..
You can put the whole stock wrx turbo back exhaust on your car... You will have to relocate the hangers on the muffler, axleback pipe, and mid pipe. You will also have to add about 4" of pipe to the mid pipe in order for it to reach the converter pipe.
I did this to a WRX turbo back system that I got for free.. It makes the car only slightly louder, slightly deeper, and slightly smoother sounding. I actually felt like I lost a bit of low end torque as well and a tiny bit more pull at the top end. The exhaust piping is quite a bit larger in diameter than the stock size, and that's what accounts for this difference.
It's not worth it.
Go pick up an aftermarket Borla or Vibrant muffler for $120 and have an exhaust shop custom fabricate an cat back pipe.
It'll cost a little bit more, but it's so very worth it. If you don't plan on modifying your engine (cams, head work, etc..) just stay with the stock 2.25" tubing diameter.