I have a round brake fluid resevoir and had to shave the hand guard just a bit with a dremel tool to get it to fit. If you don't have a dremel, get one, they are great for small jobs like this. Aside from this, they mount right up to the mirror holes, no other modifications needed.
The GPS mount is a RAM mount that I bought from gpscity.com (around $20 or $30). They sell them cheaper than going through RAM! I bought a refurbished Garmin Nuvi via ecost.com (around $80), bought an extended warranty via squaretrade.com ($10 for a year or two, I forget). I take zip lock bags with me on trips in case it rains...has been working great for two years now. I can buy a lot of zip lock bags for the price of a waterproof gps!
Attached are a couple of older photos.