IMO if you have red interior LEDs and are wanting to do underwaters, check out this thread.
http://www.wakeworld.com/forum/showthread.php?t=716011
Grant did 3 Shadow Casters (which is way over-kill for the normal person, but just looks awesome) in blue. Some of the pics he shows are with his in boat LEDs red and personally, i think it looks awesome. a lot better than red would anyway.
The Shadow Casters are not cheap (~$500 each) and if you are on a budget, i would suggest looking elsewhere. i have two Lumitec Sea Blaze 3's in green on my boat, they were like $210 each and im very happy with the light output. i can see the whole wave surfing at night, and get about a 15-20' halo in pretty dirty water. the cleaner the water the further the light will project..