C-F-M and Dominanteng both make quality parts either place is a good choice and will work fine. I have dealt with both places for various parts and have been satisfied with both. As for fitting, anything you get after market will not be flat like the OE cat however they are all designed to fit properly so dont let the difference in looks fool you. The only place you MAY run into a fitment issue is if your header is bent. The svt header sits very low and useually has a dent in it, this also can cause your cat to bend slightly. When you install an aftermarket cat or orp from anyone there is always the possibility it may hit the cv shaft or sit at the wrong angle due to a slight bend in the header, with a torch, prybar, and patience you can straighten it back out. Just throwing the warning out there so these aftermarket companies dont catch hell if the cat wont line up since it may not be their fault to begin with.