Things I'm considering:
K&N Oil and Air filters (very simple)--------> good over all upgrade
Cold air intake?---------------> I wouldn't waste your money
some kind of exhaust upgrade--------->if you want it louder then I would get a muffler/cat back, but you are not really going to see high gains from an exhaust
maybe one of these:---------->please don't (another waste of your cash)
post up some pics! lol, you might want to spend the money on maintenance and such, tires etc. and this is all just my personal opinion:
When I fist bought my truck, I looked into performance options for it... looked at CAI, exhausts, pulleys (just bolt on stuff), but came to realization that in order to get actual/visible 10-15hp I would need to spend about $3,000. Instead I spent the money on wheels/tires, screamin demon ignition coil, spark plug wires, plugs, air filter, changed/flushed all fluids, ran sea foam through the block, big 3 wire upgrade, extra ground from battery... basically maintenance stuff that would help the truck in long run.