Motorcycle baffles will probably be your best bet, but don't expect it to be quiet, in my opinion the pipes are just too short for anything to be effective in making them quiet or reasonably quiet. Alot of it depends on YOUR perception of what's liveable just remember when ever you drive the car the exhaust, and noise are coming back at you not alot of fun if you spend much time in traffic.

Also as i've warned others don't plan on keeping too much on the wall's of your garage either, everytime you start the car it blows the wall's clean.

Ron