I've been doing this for about half a year now and have learned tons in that little time, so I thought I'd throw in my 2¢... Maybe I can help out the auto people a little more.
For you auto people, go with O/D off. I'm not sure if this is 100% true, but if I floor the car around the day before the race, it feels like the car learns that style and tends to hold higher revs a lot longer and shift at higher RPM than when I drive like a granny. This can help in certain turns where you don't want it upshifting when you let off the gas a little. Also, you can learn to modulate the pedal to get it to shift around in certain ways, but it's hit or miss most of the time. There's no formula to it, you just have to kind of "feel" it. In the really slow turns when you have to slow down a lot, it will usually go up a gear when you let off the gas. To counter this, I usually punch it right before the apex so it will shift back down, then let off to a reasonable level so I don't take off before the middle of the turn.
About my tire pressures... I used to run at about 42psi in each, adjusting the rear as I see fit... but recently I've been running with ~38. I'm not sure if it's my tires (BFG G-Force Sport) but I don't go up on the sidewall and I feel much more confident driving with the lower pressures. I think it's gripping a lot better, as I would understeer/slide a lot more often when my pressures were higher.
Yes, that is a banana in my pocket.
Dan - gump
[BBS][Borla][Focus Central][Hella][K&N][Koni][Lentech][Wings West]
Wiregrass Region SCCA