The clunking in the back is most likely the wheel hitting on the edge of the fender where it sticks in toward the tires. You may have to bend the edge up, I used a baseball bat but some people say to use something else.
Perf: KYB AGX Struts Neuspeed Sport Springs 5 Strut Bars (2 F/U, F/L, R/U, R/L) Sprint Front Camber Kit $15 Rear Camber Kit Some Regrind Cams that need High Compression (which I don't have) Ported Intake Manifold Ported Throttle Body Nameless Cold Air Intake with a K&N Filter Custom 2 1/2 inch exhaust with Dual DTM Muffler Empty Catalytic Convertor Energy Suspension Motor Mount inserts Hurricane_GS Short Shifter Symborsky Shift Kit Clutchmasters Stage 3 Modular 225/50/16inch Wheels and Tires
Audio: Alpine CD Head Unit Alpine Flex4 25W X 4 for Fronts and Rears Alpine V-12 450W X 1 for Subs Infinity Reference Series 5 1/4 and 1 inch tweeter component systems for fronts and rears Blaupunkt 3 way 6x9's in the rears 3 MTX 5000 10" 12 ohm subs running 4 ohms mono
Flame Red SRT-4 GT40,8.5:1 Built Shortblock, Brian Crower Stage 2 Cams, etc etc etc...