I agree with Andy
I run a much different setup at TMS than Topeka, even if you run in a later heat there isn't as much grip as Topeka on a bad day
for reference, we ran a regional on the same lot one week before the Tour
again, STS2 ran 1st heat
it was damp in about half the lot due to an earlier rain
I ran a full 10 seconds faster on my second run after it was totally dry -- no spins or crazy stuff -- just no grip at all, sort of like ice
almost everyone in that first heat ran 10-15 seconds faster, first to last runs
only good thing is that you don't get any tire wear
FOR SALE 1993 Miata STS2
1992 STS2 Miata
1993 Miata, almost a Spec Miata for track
2003 Corvette Z06 retired to cruiser