don't forget the Kenwood Excelon XR-5S ... it's a 5 channel, built in crossover (high pass / low pass, so not good for a 3 way system, and 12db slopes, but decent) and TINY!
• Width: 9-1/4” (235mm)
• Height: 2-3/16” (55mm)
• Depth: 7-9/16” (192mm)
• 80 Watts (RMS) x 4 @ 4ohms
• 350 Watts (RMS) x 1 @ 4ohms


i have one of these beasts in my GF's Cayenne powering 6.5 components front and rear and 2 12" alpine type R subs. it's truly unreal how loud and good it sounds. this thing is a MONSTER amp in a TINY package!!! another good fit for the S, and not too expensive. low $300's from pacific stereo. i'm putting one in my S in the next week or 2.

 

This is not the only mini amplifier out there but I've been a long time fan of the the Zeff board designs. It adds up to a really nice package where you get very good efficiency without the a/d, d/a conversions found in class D designs. The signal to noise ratio is very good and the frequency response is not compromised for efficiency's sake. 3rd party tests also confirm the performance on these little guys.

I am now running close to 2,000 watts rms on the stock alternator and stock sized battery using these boards and they aren't even all the class gh design. Maybe one of these days Clarion will sell the full size 4 channel GH boards under their name. It's a lot less than the Arc version.




The Vibe 4 ch seems to be discontinued.




You can power anything you want with a 2 channel amplifier using the right passive crossover. Hoop speakers are silly however, with good drivers up front you shouldn't need them for extra output and retain the better soundstage.