Wow Paragon, you have picked a very hard goal to achieve
Those Japanese 0-300km/h cars (Veilside does it in 13 seconds flat!!) have had incredible amounts of money on them... Realistically, probably 4 or 5 times your budget when you take into account the pure time spent on R&D and testing...
Mario originally started out his project building his car not for drags, but instead for Top Speed runs. I can't remember exactly why he changed direction and aimed for 1/4 mile drags instead, but I suspect that the testing and R&D involved in setting up a car for those kinds of endurance passes would be a fearsome thing.
Heat is a MAJOR problem with the RB series engine when you get upto those power levels. If you remember those blacked out parts on Mario's website he put up during the build, they are head cooling mods that he didn't want to disclose, as that's what he thought set his car apart from the pack. They were his secret weapon.
Now he's gone through so many heat related problems setting up his engine, you'll have to face the same problems. Doing an 8 second full noise pass is a LOT easier on the engine than a 15-17 second full noise pass as you can imagine, so you have a tough time ahead of you...
Very interesting project though! Good luck with it all