I was fortunate enough to do VIR full course last year as well, my vid:
I found turn 4 to be deceptively harder than it appeared - there's a lot more track than you think but my tendency was to take the turn earlier. Also I found the car to understeer in that turn. On the esses, it's important to really maintain focus and turn on time because you're carrying so much speed that if you try to correct a late turn, it'll mess you up throughout. And of course there's oak tree - 2 cars went into the dirt on that turn during my session.