Recommended setup for Stampede/Rustler?

[RC-Monster Mike]

Yeah, 40 mph on 7 or 8 cells is pretty easy, actually. As joppa seaid, you will need to beef up the tranny. I ran the aluminum idler with some grease. It will work for quite a while. Over time the idler gear will get sharp on the back side of the teeth and start to strip the diff gears when you hit the brakes. At this point, get a new idlers and continue playing!