Stock tire width works best for a stock bike. Putting on a wider tire for the sake of appearance is pointless.
However, if you modify the engine to increase the horsepower, a wider tire works better to apply power to the road.
Wider rims can be laced on with a greater offset in order to clear the swingarm. Installation may require removing the rear drive entirely.
It works for me. I have a 130/80 on my R90S. Using an 18" front wheel helped with the turning.