Unless you are planning on serious engine modifications, ei. blower or lots of nitrous, don't box the frame. I assume that you are getting you liscense for the first time, so I will assume that you are a teenager. When I was younger, I was hard on gas and hard on the brakes. Remember this when you are considering changes to your truck. As far as safety concerns, brakes and steering of course need to be in tip top shape. I would also work on the wiring. It is not safe or fun to drive your truck at night without lights. Electrical fires suck too (I speak from experience).

Never hold your farts in. They travel up your spine and into your brain...that is where crappy ideas come from.