Start with the little things and add up I say. Most importantly though KEEP THE OLD TRUCK!!!!! I regret selling my old truck every day. Even if it doesn't get driven much, it's nice to have one that won't hurt too bad if it gets dinged/scratched. It's nice having parents that will spoil you isn't it? A few of my buds always dogged on me in high school for having so many vehicles but what they didn't know is that I worked my whole life for nothing to get those toys. So in a way, I did buy my own cars. But yeah, headers, tune, exhaust, things of that nature to start.