Try to stick to the main DSM vendor exhausts, or proven name brands.
www.bushurracing.com,
www.slowboyracing.com, and
www.roadraceengineering.com are the ones I have used. RRE makes badass downpipes, but offer the Apexi catbacks. Thats a decent combo. I use the RRE downpipe, but my own home made catback.I try to avoid the ricer brands for cost and performance reasons, depending on the case, but they might be the right option for you. All depends on the goals and purpose of the car.