I have heard from a few people who have modified (more than just I's and E's) Ralliarts, and had said that replacing the stock cat with a HFC or test pipe will be fine, and unless I wanted the sound, It wouldbt be necessary to replace the rest with a turbo back.

Im not swapping turbos or anything fancy, I would like to get to 280whp safely.
Just bought my RA last night

 

The stock cat is very restricting indeed, but it will not get you to 280 whp. That will come with a full turboback exhaust (downpipe, testpipe or hfc, catback,) intake, intercooler and piping (oem evo x parts will suffice for stock turbo) and then finally a tune which will yield the max results.

As for the test pipe or a hi-flow cat, imo it would sound really raspy with the stock exhaust. I haven't come across any ra owners that ran just a test pipe without a catback so i couldnt tell you from experience of sound. I would say upgrade the full exhaust including the downpipe, cat, and catback. There are numerous options out there for the RA. My personal favorites are the AMS single exit and the Ultimate racing single exit, which im currently running now.

 

I appreciate your input sir! I have a buddy with the AMS single, but that one isnt for me. Im really interested in the Cobb Quad tip, it looks and sounds so nice! But I cant find anyone that has it to get feedback from.