HKS has two different exhausts,
Legamax(mufflers only): http://www.burtmanindustries.c...haust
TF(full system):
http://www.burtmanindustries.com/zoompr ... ks_exhaust
Stillen(full system): http://www.burtmanindustries.c...haust
Haven't really heard a lot of information on the TF, the Legamax and Stillen usually get a good amount of praise. I believe there are owners of both systems on the board. Good sound, quality build from both companies. One complaint I have continuously run in to about the Stillen is that one side hangs lower than the other and that usually an exhaust shop can adjust it w/hangers.