Cool. Then you just have to decide what pipe to use, how you're going to make the bends, how and where to mount it, and what the finish will be. You can get straight pipe and mandrel bent 180 deg. sections from Aircone out in CA. Which is what I did, then go through the same procedure that I described. Bear in mind that if you do that, your pipes will have welded seams at every joint, thus the frankenstein look. You can wrap the pipe with heat wrap, but that may look goofy on a 175. Also the pipe is steel, so you'll need to either powder coat, plate, or paint it. The paint wears off after a few miles, and the pipe develops a nice layer of rust.
Or you might try the local custom exhaust shop, but they probably don't have the small diameter stuff. They can special order it. They can bend it too, but that might take some of the fun out of it.
Either way, you'll need to figure out the two into one joint, which might be tricky. Are you a pretty good Oxy/Acetalyne welder? It's a better way to go than mig, stronger welds with less slag.