Yeah, probably a little on the nasty side...
140/80-17 will fit. I have tried 3 different 140/80-17 tyres, but not that particular brand.
The overall diameter of the tyre is very close to the 150/70-17. It doesn't even upset the ABS.
The width of the standard rim spreads the tyre out in a flatter arc across the tread face and I get nearly double the mileage out of the same tyres on the GS as compared to the DR650.