Marine Electronics Forum - Which small stand alone amp for music

I've been going back and forth for way too long between an amp, SonicHub, head unit and nothing. Now, I think a small amp with my phone (Android) is the way to go.

I've got a relatively small space and don't need blasting music. Want to listen running and trolling while sitting inside the house, so not too much wind. I've realized that AM/FM/ipod are not too important. I'm going to go simple with an amp to the speakers and phone to bluetooth to amp. Amp will be protected in the cabin as much as a cabin can protect electronics in the salt world.

I've decided on JL-MX650 speakers (2).
Bluetooth gateway to phone (got the Blackberry one, and it works with home stereo nicely)

So, what amp should I get (as small of a physical size as possible is my goal)?

I'm looking at these two:
- Fusion Zone Amp 2 channel @ 20w RMS (http://www.fusionelectronics.com/marine/products/amplifiers/ms-am702)
- Poly Planar 2-chanel 50w (15w RMS) (http://www.polyplanar.com/product/me52-2-channel-50watt-expansion-amplifier)

They are both a nice size physically, but are they too small power wise?
Once the gain is set, is there a reason to touch it? (the poly planar has a volume control on an extension wire)

I've got a Fusion Zone Amp installed ... works great.

http://i676.photobucket.com/albums/vv129/bluewaterpirate/Two%20of%20a%20Kind%20Electronics%20Box%20Redesign/2-10-1.jpg?t=1330350114

Here's the sound reproduxtion I get ......

http://bluewaterpirate.phanfare.com/5431412_6214713

Thanks BWP.