Can't remember what the output of the L stator is, but an easy improvement is a good bulb. Trouble is, where do you find a Bosch BA20d bulb with a decent output? I think the biggest mass-produced one is the 35/35 Osram. A guy in the UK is importing from Aus' these:
12 volt 55/60 watt Bosch/Ba20d HALOGEN bulb.
Improve lighting by up to 100%. Per pair.
Find them here:
The site is run by Tim Hodgekiss; very nice guy, quick and efficient.
The bulbs sound expensive, and they are. However, bear in mind that they are made up in a craft-type environment in small numbers.
I put one in my XR600 and it works a treat - v.v. bright compared to stock. I have the Baja Designs re-wind also by the way, and this is very handy.