I have it and use it regularly.
1. There are no clearance issues on the R3T. I can't speak for the Classic or Roadster.
2. It works very well. Allows you to set high and low pressures and will warn you if either is exceeded. It will also advise about tire temps - important down here in South Florida. Gives an illuminated and vibration warnings. Just be aware that the sensors will "go to sleep" after about 20 minutes at rest, so it will not update cold tire pressures unless you rock the bike back and forth a bit.
Well spent money.