If your goal is 300HP at the wheels you will have to do a lot of major engine work. I have dyno'd at 258.6 HP and 294.9 TQ with 3.73:1 gears, LT headers, off road H-pipe, underdrive crank and water pump pulley and stock alt pulley and stock cat back. I didn't get the car dyno'd after I added the Densecharger and Superchip from PHP but judging by the difference in performance I feel certain that an additional 10 rear wheel HP was gained and that my overall HP curve was extended. More "significant" power lies in the intake and at least Paul Svinicki of Pauls' High Performance is working on squeezing it out. However, when I last spoke to him and Ronda it appears that it won't be ready for production until after the New Year. Houston Performance sells a more aggressive cam and head package but I haven't seen any numbers on what that combo would add. Hope this helps
Arthur