I dont know about on the trails, but putting 35w 5k HID's in my 4runner was a 200% improvement. Check out xtremehids.com its off of 1-40 and Rock Creek Dairy road near Greensboro, they are also on e-bay.
Also if you dual fillament bulbs (hi/low) they will be expenensive ($125). I bought just the low beams ($65) and failed safety inspection for no high beams. Had to re-install original headlights to pass.