i have the hks. i just installed at the end of last month. one thing i like is that it is a cat delete so the piping only gets cut once. also it is one of the few exhausts that is 2.5" inside diameter. there are two mufflers and one resonator. its a direct bolt on. if you diy some of the hangers are hard to get off near the rear cuz there is little space. my bro used some flat head screwdriver bits and wedged them between the hanger and metal to get them off.
i can vouch that it fits an 07 hatch non pzev.
the sound is great. its also not really loud. with the windows up, radio on between 15-20, and cruising at 75 i cant even hear it. when you accelerate it comes alive. its just awesome. no drone at all.