I ran the sub off channel 5&6 because I thought it was ample power for the sub and I didn't want to waste the quality AC channels on a set of rear fill speakers. I was wrong, the AC bridged channels were decent but lacking a bit of power for my sub considering the active stage in front. So I pulled the Infiniti amp and replaced it with a pioneer mono block 800 watt amp. Now my sub has plenty of power and the rear fill resides on the AC channels 5&6. Also ended up buying AF tweets and replaced the Hertz tweets on the dash. They were just a bit bright and didn't care for them, the AF's are damn impressive.
The AC DSP amps are good but the software is buggy and the tuning aspect of the software is not very friendly. If I was starting over I probably would've went a different route but it was too late in the game to change.
As for accubass, it works but with a remote bass knob you'll find that it's not needed. I set my amp to turn on the bass level to a reasonable level, actually a bit low. Then when I get in my truck and drive if Im not in a jamming mode I don't find myself having to mess with the knob. If I want to rock some tunes, then I dial it in on each song. Works well. So I've switched accubass off.
As for a good signal, you'll be fine. The stock head unit isn't too bad. Basically I don't exceed 3/4 volume and everything sounds clean. I could see some clipping after 3/4.