so im in need of a sub / amp for my 2000 audi a4. the subs gotta be about and 8 or 10". my friend has offered me a poweracoustic amp for $100. would it be smart to get the amp and buy a sub online? if so what kind of sub. and if poweracoustic amps suck please tell me. im pretty sure they no longer make this one. for some reason saphire version comes to mind or something. plzzzzzzzzzzzzzzz help