I'm pretty sure I was red-lining it in 2nd on my way into that big sweeper. That should put me right about 50 MPH. Then I'd just let up a little (and tap the break), flip it sideways and gun it again. Then presto! four-wheel drift! Wooo... hooo...! Of course, it took me 10-15 runs to work up to that.
I'm going to try to capture some of that video on my PC. If I'm successful, I'll post what I have of your run. It was my buddy Curt's (Turbo4me) wife who taped it. There's really not much there, they were mostly taping me. Keep an eye out for more Prescott Rallycross posts.