for what it's worth.
Several I know have put this on their bike or boat over the last year.
http://www.gooddeals18.com/product/...__yacht_2_speakers__amplifier__radio_pkg.html
$85 for a 100 watt amp, 2 marine speakers, internal fm (probably not too good considering the antenna) and even a remote. all in a tight small package.
just got this in and I am pleased with it.
steve saunders website shows step by step to tap into the radio and solder another device and void the tape deck.
hoping these speakers will fit in the back.
the amp will boost the bike fm and mp3.
a male/female cable will allow you to put the aux jack wherever you want.
I am just starting on this so I can't say it's a great idea but it is the direction I am going.
I can then play the mp3 or radio thru the speakers.
I also have just bo't a set of speakers for the helmet (amazon $20) with a jack that fits the gps.
I am going to splice this so 1 speaker will let me hear the cb and the other the gps.
don't care if they are stereo anyway. It is the only way I can figure out how to get it all.
good luck and if anyone has a better way, I am all ears.