The reason you're stripping screws is because you're not using a decent hex driver. Pick up a set of MIPs, they'll last a very long time and won't ruin your hands. Once you start using a hex driver, you'll notice that the screws you thought were stripped, are still good. The same thing happened with my vaterra Kalahari (uses very similar hardware to the mini 8ight).
Hot Racing and Robinson Racing sell hardened steel gears for the the mini 8ight which will fit this. Make sure you pick up 48 pitch gears, and they should also match hardness.