We're not talking extreme turbo here. Just a Drag gen 3 kit with big injectors and aem ems. I've seen some setups with 2.5" exhaust and some with 3" exhaust. Which is better? I'd rather get the exaust now and turbo later (help space out the spending a little bit), but I dont know if 2.5" piping will help or hurt for a pretty close to stock NA B18B. I know 3" will slow me down some. Who makes a quiet, but deep 2.5" exhaust? What about 3" exhaust?

The other question I have is mating it up with the cat. I know leaving the stock cat on with new piping, whether it be 3" or 2.5", would hurt me more than it helped, so I'd be getting a cat that will mate up with the piping. Can I have a shop fab me up something so I can connect the stock downpipe to the new cat?