The truck I drove was Larson Millers at Firepunk Diesel. That is where I got my transmission built. His brothers truck puts out like 1400 hp. He won the Diesel Power Challenge this year and had a picture on their FB Page of the winning truck towing another truck that broke down home from the event.
When you get to 500 hp your truck should be 13 second capable. That is faster than many factory muscle cars. Lavon at Firepunk told me they are getting 550 hp out of stock 06 trucks with just EFI live tunning. I'm sure if EFI is available for your truck it should be about the same. Don't waste money on un necessary mods. A lot of guys do. Lavon said he put a new intercooler on a 1000 hp truck and it made 12 hp more on the dyno. That mod would be a total waste of money on a lessor hp truck. Good Luck,