I had similar problems as previous reviewer, but I had to file off some of the upper deck as well. After flipping the belts, the battery holders need to be modified. I also drilled an extra couple of holes in the chassis so I could move the mounts around a bit. Took some fiddling but it can be done. The rear battery mount needs to be removed to adjust gear mesh which sux a bit. It might be stronger than the stock motor mount, hard to say. I'll crash a few times and find out ;) Its cheap, and it looks nice, so 4 stars.
This is a great part. Only "problem" I had with it, was that i had to change which sides the belts were on, because part of the motor mount won't allow the front belt to be placed on the left side (left if you see the car from behind). Additional problem with this, is that you most probably have to file/cut off part of the inner battery mounts, or these will interfere with the new position of the front belt. This obviously leads to the battery not sitting properly, and it can easily bump into the front belt. This is easily fixable though - personally, I just took a couple spare pieces from the battery mount, and put them under the upper deck. (There should be plenty of spare holes in the upper deck to fix this).
I'm also not sure how this will work with 1 way differentials, si..