DC2 exhausts are a direct bolt on I have been told. So as mentioned above one of those would be best.
I don't recommend going custom as sometimes they can be quite restrictive.
I had an Apexi N1 on my coupe in the past. Although the flow was quite good, the sound wasn't very impressive and it was a huge great big tail pipe!
I have a DC Sports now on my coupe and that is good. I'm still running the Apexi Midpipe which I want to change to one without a box.