Grenade-I truly believe the pipe thing is the way to go, especially making our own bends. You missed it I was TQ for a few minutes today

And then "Atomic" Eric Burkett took it

and never looked back
Rev-I've got some ideas and relatively simple. Like cinder blocks tied to a servo and transmitter driven

Honestly If you've not seen the one at RatRaceway you need to check it out