Your first alteration should be to buy a Eastern Beaver headlight relay kit and install that before even changing out the headlight enclosure. It will do wonders for the longevity of your handlebar controls. Stick to the standard 55/60 type H4s otherwise you risk melting the OEM lamp connector if you go for higher wattage. High watt lights don't put more light on the road necessarily, because it depends a lot on the lens system being used in your replacement housing. If you are intent on using higher wattage H4s, then swap in a ceramic H4 connector for the OEM.