I have always been one to believe that the manufacturer knows what is best for your vehicle. Sure, cosmetic mods and comfort mods are likely safe, but going from a 14 inch (or is it 15 inch) tire to a 17 inch certainly not only throws off your odometer and speedometer, it might also throw off your VSC system and change your center of gravity, thus making the bike more dangerous.
The Spyder is unique as it is...to me, I'll make it brighter from the front and behind for safety reasons. I'll add a few creature comforts and safety features (mirror extensions and the like), and a nicer exhaust system, but I'll never modify the core elements of the bike such that it could make it more dangerous on the road.
It's great to have a 'more' unique bike, but if it's more likely to get you injured, it's worth no amount of money....