If I install a set of lower compression pistons, 8.6:1 or whatever, what will it sound like? I am putting on a 3" Apexi N1 catback, and catco 3" hiflo catalytic converter. I just don't want it to sound like a GST. They sound like dump trucks.

Lowering your compression doesn't make a difference in sound.....at least, it didn't for me. Your exhaust is what makes up most of the tone of your car's sound.

yea, i think you'll only get a change in tone if you substantially change the bore. 2.4 L give a different sound

Well from my experience, lower compression motors have more of a blat to them than a hi-revving sound. Just wondering thats all.