Posted for Pat Weston <peweston@yahoo.com>:

 Besides thinner (barely) wires, the alternator will be
 the same size and effeciency as the 14V one. I fail to
 see any other advantage. There are many downsides, the
 plethora of automotive electrical part are now no
 longer accessable and you'll be limited to certified
 (read expensive and hard to obtain)aviation parts.
 
 Pat