Haha, we'll see. So far I really like how the 18" sounds. Its got a very nice deep tone but its not overbearingly loud. So far its perfectly quiet during highway and street driving and only comes to life when I get on the throttle. Its my daily driver and I drive allot, don't want to turn it into something I'm not going to like driving.
Also, it might just be me but the butt dyno really feels an increase in partial throttle torque and horsepower around 3 to 4krpm. Definitely, feels like its breathes better.
Probably just me though.