There won't be much difference between any quality DP. You need a hi-flow cat and that is going to be the most important aspect - where you want to focus your investigation. Also, make plans for your catback now if you are doing one so that you can get one that matches the DP flange. Invidia, Nameless, and Cobb are probably the best places to start. The catback literally makes no difference (unless something weird is going on with the new cars that I'm not aware of).