Very complicated if you want to make "doublecharges"
They are slow with Tomymotors. The Tomy 3.0 dont even work.
Some controllers cant use Hi-performance AA-batteries.
The LXX-motor you get with the car should be very fast. One of mine are very fast. The other is not. I have tried to send it back but the new motor i got was as slow... I have heard more people having problem with slow motors.