one car i got a li-Ion 2 cell 2600mah pack with hobbytown regulator0m,
one truck with 1600 duratrax 5cell Nimh
another with 2300mah Lipo with turnigy regulator
will never go back to Nimh, it looses voltage so fast when using 2 digital high toque. but always gotta remember to turn it off and always double check