Another really trick way to semi-lock the gear diffs is with silicone dielectric grease (aka: "Tune-up grease"). It's really thick and it doesn't get thin when it gets hot. It makes the diff act like a really smooth ball diff. You have to buy a decent-sized tube of it though, because the little packet isn't going to be enough to do a diff.
I have a Ta03 in mine, cranked WAY tight. It's pretty easy to drive, but it does push on power quite a bit...just like a real FWD car. It's pretty easy to drive, though.
I had a 5800 Novak in it for quite a while. (never stripped a single gear)
It was pretty funny seeing a Mini running down 19T cars on the straights.
