What sort of ambient light will you be working against? The XP3 is a good light. I tried one out for a few days), but ended up returning it because it just wasn't bright enough. The movement is a little slow, but not bad. And the coverage was really good. Four of these would make a good show, as long as it's dark enough (and better if you can have fog).
I know it's more expensive, but maybe give the Auto Spot 150 a look. Also a 150 watt lamp, but it's discharge which should be a lot brighter. These are about $800 a pop.