its not really the amp, its car(air space) box/port size. I gotta buddy who hit 148.7dBs with two kicker comp 12"s n a ma audio hk401SX in a durago. SUVs own with air space. I have yet to meter mine but im definitly in the 155-160 range with a silverado. my box is about 200 lbs, but it gets it done.