Replacement 1156 and 1157 right-angle LED lights are available from the same company, superbrightleds.com that will point all of the light out the back end. See the link below for photos and specs:
http://www.superbrightleds.com/cgi-b...x30.htm#photos
I am not sure of how bright these are in comparison, but might be worth checking out if you are considering a simple conversion.
If you want the real deal, check out Mike Del's upgrade at:
http://www.uniquecobra.com/forums/showthread.php?t=7540