The stock projector setup on the Sky is actually pretty good. However, a 55W halogen/filament bulb can only produce so many lumens. You can always go with a 35W HID/arc bulb that produces about about as many lumens as a 70-75W halogen would. If you upgraded the wiring, which was common way back when, you could run "off-road use only" 85W halogens. For a few years now there have been 55W HIDs that produce literally double the light of the equivalent 55W halogen. And pretty affordable these days too. You can get a set for $150ish from a reputable company. Make sure you stay in the 4000K range. Once you get 5000K and above, you start losing lumens/light output really quickly.
I got my set from a friend of a friend that's a licensed distributor for a few brands of HIDs, and got a second set of bulbs for free, so I got a 4300K, and a 6000K. HUGE difference in light output.
Edit: whoops, typed 4700, not 4300, which is what I am running.