Originally Posted by Granpa

The only way to find out whether you're any good is to run with the fast guys. Most of them run the TCS races. All the rest is just BS. As far as I know, they never run more than 10 cars in a heat. Since they usually have a Tamiya rep at a TCS race, I seriously doubt if that ever happens.
Packing a gear diff full of oil or grease only accomplishes the creation of a big mess. It only stays tight for a little while before it all leaks out. Most people who run a gear diff use shims and the heaviest grease they can find to slow the diff action down. Even then , it will loosen and you're rebuilding the diff. A better solution is the ball diff from a TAO3 with the diff screw bottomed out and put in with a little LocTite. If installed properly, it won't loosen.