i have one alpine type R 05, ran at one ohm on my hifonics bx1500d, thats 1500 wrms or 1380 whatever, either way i have the gain about half way, maybe a little more for daily it takes good, i can almost hear it saying i want more, but im afraid to, o well , and it sounds better than the 04 too, ive owned one of each in practically the same box