I've been doing this forever (first competition event in '87). I've used old school 80's Rockfords, had 4 a/d/s/ PQ20s in a 4 way active setup, McIntosh, a/d/s/ P series, Memphis Belle, JL Slash, along with some cheap stuff (Coustic, Pioneer, Eclipse, Alpine, TMA) in secondary cars. Gotta say...