I'm running regular H4 bulbs with the stock wiring (MC28). They are rated 55/60, as opposed to the stock NSR bulbs which are 35/60, so in theory they are still in spec for what the wiring is rated to handle. The only issue was getting the H4 bulbs to fit, as the retention tabs are slightly different. I bought a set of bulb converters made for a ST1100 (they use the same stock bulbs as the NSR).

I've been reading the threads about the 250 and 400 gray bikes blowing the regulators when they change to higher wattage bulbs, but I believe that they have 45/45 stock bulbs.