Get a gryphon and leave it alone if you are not going to pay it off. Maybe level it and inspect the truck for anything it needs like said above. Shocks and so on.

general upkeep is most important before anything else, period.

Small audio stuff, nothing crazy.

Personally my 06 has a little over 50K miles and what I would do is buy a second car/truck if you really want to work on the one you have now.

Don't spend all of it, on the truck
Or
pay it off/down
Or
Buy something else that is cheaper to modify.

I am pretty sure for what parts on this truck cost you could build a older truck for 1/2 the cost including buying the truck.

I remember back when the show trucks was ran by Stacy D, he built some crazy stuff for under $3K.

I think for one this is your DD and killing the MPG is gonna hurt in the long run, the cost to mod a 04-08 is much higher than older trucks, and 2K is a lot of money.

Like I said, first thing I would do is pay off my debts, like my bank loan and my monthly on my credit card and paypal not counting my TV payment and my truck payment.

But, its your money.