I'm a little late to the party sorry.
I have a sc10 4x4 kit that i built about a year ago now, and ive never raced it, I dont have any nearby off road tracks thus the lack of motivation to drive somewhere else for just 1 truck. I have the Castle sct combo with a 15t pinion(as of tonight haha) and it flys, its a blast to drive considering how different it is compared to a clod or wheely king. The clicker is really cool, I use it when im inside in a tight area, truck turns on a dime. I jump it off a lil wall, up a small thing onto outdoor carpet now steps and back up steps a lot(typing this out makes me seem harsh on my truck haha) and it handles it, When ever i do race it its fun and easy to drive. Complaints is that it was mainly only kit at the time, and with me never owing any a-arm truck i was lost 90% of the time in less it was putting tires on haha. Sc10 4x4 is a lil hard to work on, if anything where to get hurt in the front or rear gearcases i'd just head home haha, have to take A LOT apart to even access the gear cases. But ive used the truck a lot and no problems with the belt at all if you dont set the belt up by factory standards, look and read around, use some of the pros setups as guidance on the associated site(thats what I did, heck there was only 1 setup then).