My E-CRT has been through three revisions. I'll save you the long story and say this:

1.) NO WAY to make it work without a motor mount like Mikes (something with the motor and diff on the same metal!) I had a 2 pc and it was a nightmare.

2.) Hot Bodies Ring & Pinion help with gearing. Currently I've got the HB R&P on the Diffs and the Kyosho 46T Spur mating up with a 10T Centrury Pinion all running on 4s...I'm currently using one of those mystery XLT-1 Motors which I think is somewhere around a 6XL or 7XL.

3.) I've had the batteries in both the one large block and the side by side setups. I prefer the side by side...the truck feels more balanced.

Here is a photo of my current E-CRT...