Just some notes (since we replaced the tire on my C650GT tonight).
You know those two little red dots the tire manufacturers put on the tire to mark the lightest part of the tire? Traditionally you'd line those dots up with the valve stem since NORMALLY that is the heaviest part of the wheel. However, if you have the tire pressure sensor, that thing is a LOT heavier than the valve stem; you really want to line those dots up with the sensor, NOT the valve stem.
There is not a whole lot of wiggle room to remove the calipers. Be patient and take your time. Also, watch out for the ABS sensor on the left side of the wheel; you'll have to remove that to get the left caliper off.
Finally, my friend showed me a neat trick I didn't even know about (it worked on his R1200RT and he wanted to see if it worked on the C650GT too). When the bike is idling, press and hold in the turn signal button for five seconds, then press it to the left and hold it there for five seconds. The headlight will go out. He said the feature was there to allow you to warm up the bike in the winter and allow maximum charge to go to the battery while idling. Once you get moving at a certain speed, the light will come on by itself. You can also make it come on immediately by flashing the high beam.
The things you learn!