On the MFU you should actually have a couple of open slots for extra lights. You will just need to get the right connector to plug into the connector on the MFU.
Check out this link and you about halfway down you will see.
http://www.tamiyausa.com/articles/bu...e#.U53X92dOVUS
When I did my knight hauler I just jumped off of other lights but made sure I checked my voltages and currents so I got the right LEDs to work with the MFU. I ended up putting LED's in the air intakes and 4 LEDS on the back of the bunk and to this day I know everything still works fine.