Sammy, The Cateye EL500 with an SSC LED will be easiest and the "biggest bang for the buck er sterling". LED Form factor means size but also Die (phosphor square) height. Lenses are made to focus on this height. Luxeon LED and SSC share this height. Cree brand has different height so would focus wrong... The EL 500 (excepting EL500G in Germany) use "simple" electronics. It just resistors restricting the current to (280mah I believe). It will not get very hot at this level and Cateye made sure of it :-) for a good reason (so it don't melt)! The other light powerbeam needs well "everything" Heatsink,electronic driver,LEDs,lenses plus 4 cells instead of 2. Too much to bother with,not a very good host imho. That said I have an EL500 and the beam pattern isnt the best, and they fragile.. What you'll end up with is a super bright Hl EL500 almost twice as bright. For the price and figuring how its done its a decent deal. The SSC and Cree can be driven at much higher levels (1amp+) and brightness with heatsink and better electronics with much less runtime.. If it doesn't work or get broken somehow you can take your SSC Led and move on to bigger things.