That is correct. Most 5 channels have a class D sub channel. But they still use the same power supply! I won't disagree that more power is better, that should be obvious, but a single 4 channel will give him similar results to what he has now, and it would be in once chassis. Again, not sure if that's the main concern. The ID Max is a dual 4 ohm driver? If so, he would be getting less then 300watts right now?

Hmm after reading all the comments im not to sure what i want to do now, i wonder if this amp would suit my needs a little better JL Audio: Products
Mind you I probably would only end up using the subwoofer and front channels but i may opt to use the rears in the future.

BTW john thanks for your input to, the IDMAX I currently have is a dual 2 ohm. The main thing i am really looking for here is for the same sort of sound quality for my fronts and acurrate clean sub bass, i dont really needs tonnes of power as I dont ever really turn it up that loud. As long as I can hit the numbers I need to hit in the RTO testing then im good. I have actually really been wondering if all that power I had for my sub was just going to waste all this time, im told the IDMAX is a pretty flexable sub in the amount of power it takes to run it so maybe I will be ok with slightly less power. Im really at odds with what to do right now, either keep my old amps and buy bigger alternator or going with something more efficient. Its a tough call.