i got Apex i N1 Cat back... not loud at all... its ALOT quiter with SR20DET cause i have had both SR and KA and SR sounds MUCH better KA is loud SR is deep and toned... save up get a good motor not a pos KA which will pop under boost... (unless you build the motor) but then your gonna be pissed cause you will be shifting at 5500 rpm lmao... save the head ache get a SR... and toss exhaust on it...and dont listen to ppl saying SR takes long to boost... i made full boost at 2500 rpm... lol... and my buddy had S15 BB turbo and made full boost at 2300rpm. =]