15s are deeper bass but 12s need less power and produce good mid bass, if your getting a SUV definately go 15 then you can expand to more 15s after you get it
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'02 Subaru WRX 2.5L, SR40 turbo, MRT TMIC, RA gears, ACT clutch & flywheel
'06 Chevy Cobalt SS GM Stg 2 G85 lsd
'94 Acura Integra GSR sold
'99 Isuzu Rodeo 4x4 2" lift, Procomp 9000 shocks, 20" Procomp Knight Khrome wheels sold
'92 Acura Integra RS sold
'04 CRF450R '86 TRX250R