hi B
i've been using this box for over a year now, best for the money, nothing ever has gone wrong with mine, maybe duratrax is not know for making quality cars, but as far as accesories they do good
the wheel in the box can be moved so it can be mounted seeing the box from the top in the "y" axis or the "x" axis, so you can fit on or off road car on it
if you are using this box to start a .12 or .15 engine you'll do fine, i use it to start my rex p5 and it struggles a bit and shreds the rubber wheel but it does a good job starting the tight .21 considering it's meant for 1/10 cars and .12-.15 engines
hope this helps