Bulbs are easy to replace, I used the regular Sylvania Silverstar, That and aiming the headlight was enough to fix the poor visibility for me.

My only experience with an 80/100W bulb left me looking for more light. Don't know if it just a bad bulb or what, but it was actually dimmer than the stock one. I think it drew too much current for the bike it was in. I replaced it with a PIAA H4 in stock wattage and it was MUCH brighter. almost too bright, the glare off the highway signs was distracting. An 80/100 PIAA would have been too bright.

And FWIW, Even though WalMart sells the Silverstars and has one that says 65/45 for motorcycles on the package, look carefully at the bulb itself, the ones at the Walmart here were the standard automotive 60/55 in the package.