5 things to look for in an aftermarket head unit ( IMHO )
1. single DIN
2. look for a 'marine' unit, they often have ALMOST matching silver faces.
3. look for 4v pre-amps out ( no big thing, you can use the speaker out wires if necessary )
4. bluetooth built in
5. ipod connection

this pretty well trims the list down to the Clarion M303 .......
Clarion M303 CD/USB Marine Receiver w/ Bluetooth & iPod Control
or
http://www.crutchfield.com/p_020M303....html?tp=61758