Want to build a beast! But where to start?

Hey guys so I have wanted a truck since I was a little boy and finally have gotten it. 2007.5 GMC 2500HD DIESEL color white. But now I want to make it my own with mods. Im new to the diesel forums and needed help. Where should I start? I have about 1000.00 every three months to spend on my truck.....given time I could do all of the mods at once but I want to start now.

So here is my question. Exhaust? Programmer? Lift/Level? Tires/Wheels? Other mods? Which would (or did) you do first. I know that some mods have to be done before the others. Talked with NorcalNick and im going to go with 4in lift and run 35's or level it and run 295/55/20's. Exhaust will get DPF Delete programmer and pipes. Mpg's a plus not huge factor since I drive 20 miles to and from work every day. Want this thing to turn heads!

All opinions welcome. Thanks for the Help.