A lot of the newer ESCs do include protection for Lipo cells, especially the brushless sets. Best to check the spec for them individually though.
Your old reciever and servo should be good. Do double check the pinout as old KO gear was different from everyone else. You may need to change the pin over on the ESC. Check here:
http://www.kopropo.com/america/index...d=23&Itemid=61
Scroll down a little.
James