I also agree with 9krpm's line of thought by keeping it simple. I also think the event should be run similar to the rev speed time attack style. ie. Run what you bring. Any tyres are accepted except for full slicks. This means if entrants want to run and be competitive they would need to run R compound semi slick tyres.. sorts out the serious competitors. If someone has a fast street car, then by all means enter it! But don't have a sook about someone who's spent more money on modifications. It shouldn't be mandatory to run R compound tyres, but if you want to be fast then you would want to be. This also avoids dispute over street car/race car - it's not relevant. It gets too technical to differentiate between the two. I wouldn't want to watch an event with street cars having a crack.. purely because it's not that type of event. It should be for the fastest cars to battle it out in an "open" class. If some competitors say it's not fair because they can't afford proper tyres, then bad luck!! This isn't some sunday cruise event. There will also be differences in power to weight due to different model cars, chassis construction, suspension setup, weight reduction, etc. so how difficult would it be to regulate that? The drivetrain type should be noted in the results, such as RWD, 4WD, FWD. It should be for any car, in whatever trim people choose.. I say all mods should be free, with the exception of full slicks so how do you like them apples?
Edit: if this event was to ever happen, I wonder what the autosalon circuit battle organisers would think. hehe