Yeah the 550 is good enough for me too but I just started wearing reading glasses so I see a bigger screen somewhere in my future.

I would not put a permanent mount TP on that badass bike BP, make it deetachable and get the smallest sleekest one available.

 

Don't forget the additional $150 for the Harley harness needed to hook up the GPS into your stereo system, $35 for fairing mount, plus mechanic time, unless you're gonna rip the fairing apart yourself..

 

Its a half hour job to mount the thing.

 

Are you aware of the key differences between the two models?

1. The 660 does not have a "security screw" to keep folks honest. You can just walk up and pop it off.
2. The 550 has some "glove freindly" buttons on the side that are handy in the colder days.