For those of you who want more bass but don't want to sacrifice your spare tire or hatch space, I highly recommend this spare tire mount subwoofer : r/GolfGTI
Don't Hookup Your Subwoofer Until You Read This - ecoustics.com
American Bass 12" Slim Subwoofer 1500 Watts Max Dual 4 Ohm Car Audio ES-1244 - Shopping.com
Tire Well Subwoofer (Work in Progress, so don't judge me yet :-) | Pontiac G8 Forum