All you need to get 500hp would be a basic supercharger at around 7-8psi, and maybe some exhaust. Thats all I have, and if I got a custom tune done it would bring that number up to around 550 to 575hp. IMO don't waste your time with all the little bolt ons that end up costing more than a supercharger and provide 100hp less. Oh, about the LS1s, there are always a few that make the grade, but you will have no problem with 90% of the corvettes, z28s, and trans-ams. Of course, the best bang for your buck will always be gears.