under drive pulleys

I've got a 1998 Mustang GT with a Cold Air Intake, Dual Catback Exhaust, 3.73 gears, and a short shifter. The car is also lowered 1.5 inches and I believe it has an aftermarket throttle body but I'm not entirely sure on that one. Currently has about 162,000 on it. What kind of mods should I be...

i put under drive pulleys on my car and i couldn't get the alternator pulley off i tried a breaker bar a strap wrench the bolt keeps turning on the inside

I have a 1500-2000 watt audio system in my car wht pulleys can I get tht will not effect my audio system