That is a very tight track Mario! It looks as if you stay in 2nd gear for most of the time?
I wonder if a little negative camber might help out with the oversteer, meaning that when the weight is on the outside wheel, it will be more upright, and therefore present a better tyre profile? Just a thought.
It's good to seeing you using all the revs and all the track, that's what this sort of driving is all about. We need more now!