Yep, PAX matters!

Re: tire pressure; I wouldn't recommend dropping it to 30 quite yet. Start at 40, chalk your tires, and go from there; the optimal pressure is *probably* close to the lowest pressure you can get away with without tire roll-under, but it will take some trial and error to get it right. It's easier to bleed out than it is to add, though. I'd also recommend taking notes so that you don't forget what you learned, or else you'll come to the next race getting all the previous numbers confused. Keep consistant with which guage you use, too, as no two guages ever agree- in this case, it's mostly trial & error, so it doens't matter, as long as you're consistant.