David,
I think (maybe) unknowingly you are in the right place. I have run 15's for the last few years, and for me the biggest mod to these cars is tyres. I'm not that concerned running against cubes, blowers, HP or any capacity, but tyres on these cars is the biggest mod, and seemingly given lower ranking than HP and capacity.
All that has been said is good input. I give the organisers great credit, it's job and a commitments I don't have at this point. So anyone who is willing to spend good time getting an event together where we can all go for a blast and share tales at the bar gets a big hat's off from me.
Will I run 15's again this year.... let's wait and see
Cameron