Here are a few threads you should check out for information about specific areas, this list is not intended as a replacement for searching.
Search before you post!
This is not a complete list but it is a good starting point.
Joysticks/Controllers
Crab/Swerve Controls:
RF Tether/ RF Communication:
Backup Battery:
Victors/Spikes
http://www.chiefdelphi.com/forums/showthread.php?t=33275