take a 55 gallon barrel to an airport close by or buy a 55 gal barrel of race gas & proportion in however much you need. I think most of those additives are snake oil (some help a bit) and if you're compromising your adv curve (which only helps a bit & has serious downsides) or water injection or any other bandaid you are seriously limiting your eng's power potential. If you build a monster you gotta feed it what it needs.