There are tons of hop ups, there must be something somewhere, don't remember where I saw it, prolly expensive. I know there are metal trannys w/ metal gears, etc... I'm rough on mine too, during the first few tanks I've managed to bust two A-arms and 2 shocks when I hit a dumpster, skidplate, and gnarled up my bumpers pretty good.... Hit my lampost too...
The tranny has never been a problem for me, just don't rev it when you jump. I would just get another stock gear for now, there only a couple of bucks. If you do want to mod it it's gonna be expensive. And remember metal isn't bulletproof either, something is going to give eventually, even if it's completely metal. Hitting something at almost 40 is gonna cause damage....
Cheers