Those pdx amps are excellent. I have used a few of them and they are better than any rockford, kicker or ppi amp i have ever used. And this is going back 20 years worth of amps. Im also running a 900/5 jl audio hd amp. Im very impressed with this amp as well. They are both great amps and for the footprint cant be beat. Jl makes a 700/5 as well. The difference is 200 watts less to the sub and a little less cleaner than the HD.