my advise is to leave it stock and if you break em go RAs... they should be plenty strong for a VF34 unless you drag race very regularly or something. Chances are good if you keep a stock clutch on there that your stock tranny will last anyway.
Going in there and replacing the gears when everything is still working doesn't save you money over waiting until they break. The only real reason to do it that way is that you can schedule it better rather than having it just happen. Still, it's a lot of money so I'd just stay stock as long as you can. Remember, stock clutch!
2015 STi: Still Stock
04 STi, 04 WRX: SOLD