Save up and do both. Not sure how the deal is one or the other....IC = $500ish vs Valvetrain upgrades = $100
I'm more of the type of person that does everything all at once. Saves on gaskets and fluids if you do it all at once.
As far as the stock trans with VS cam and full IC you'll get a lot of different answers. Expect to make ~280 - 300whp with that setup (some will say higher some will say lower) Stock trans should hold find but it is very dependant on your driving habbits. Drive it like you stole it, don't expect it to last long. I would always suggest shift kit and bottle of Lucas additive as a precaution.
