Damn Jason, I just got done reading the entire TC5 800 page thread!!! not.. But anyways, if I had time, I would.. The last time i ran my TC5 I was geared 78/35 for a final FDR of 4.45... I have no idea if the target FDR should be lower or higher.. Maybe someone could chime in and let me know if we are on the right track (no pun intended). I am running on the same track mentioned in OP's original post..
I think i need to pick up a thicker top deck (ICF?)... I did some asphalt running also a couple of years ago and I think I still have that (thinner, more flexible) plate on the car.
It has been a couple of years since I ran some touring car, but I am ready to give it another shot.. See you at the track!