**MAJOR SPOLIERS**
In both KOTOR games, you can use ANY I mean ANY force trick regardless on what side you're on, Let's say you can be on the Dark side and you can still use like heal in stuff, In the Light side you can still use things like Force Choke or Force Thunder, It just costs alot more FP (Force Points) than usual, This is why I always try to stay in-between the two.
**END SPOLIERS**