If we still need to, I’ll designate my 2000cc run as my “official” run.
I did run the NR4s first, as I wanted to keep the fun 2000cc to last (I decided on which was my official run before I turned a wheel). The NR4s are definitely different to the Group Bs. Initially they felt horrendously slow accelerating from a standstill, but that feeling has started to pass. You can really chuck the tail out compared to the Group Bs and still haul it back, which is really fun. Hairpins are a bit tricky, as I have to do a full Scandinavian flick plus handbrake to get them around, but timing it so you hit the apex is also difficult. I did manage one time where I went around one of the bales less than a foot away from it, which felt awesome. Another time I over-rotated and accelerated into the tree at the apex, so still room for improvement. 
First three stages went OK. Stage 1 there was a blind 3 left that was much tighter than I was anticipating, shot off the road, whacked the rear on a big group of rocks just off the track, and went spearing in to the undergrowth. Got it stopped and was turning around, but went too far the wrong way and got a 40 second penalty. Looks like @keets must have done the same, as we had very similar times for that stage.
Ran the last 9 stages for the NR4s last evening and had a great time. Stage 4 @keets and I were quite close. I was up by 0.2 seconds at the first split, but down by 0.2 seconds at the second split. Gained some time after that, but still only a 3s difference at the end. Rest of the stages I was the trailblazer again, except for @TeTeT, who had sadly retired earlier on.
All of the remaining stages felt really good, right up until the end. Stage 12 had the same corner than caught me out on Stage 1, and while I did drift wide on the same corner, I managed to navigate around the rocks and back to the track with no extra penalty. Looks like @keets wasn’t so lucky and bought the farm in the final stage. Tough luck, as you were looking good up to that point.
Looking back at when we ran the 2000cc class last time in New England, my NR4 run was almost 50 seconds quicker. I think that’s down to a few facts: I didn’t have any punctures in the NR4s, the rest stops at each stage meant I could run soft tires all the way through, and we’ve improved as drivers and learned a bit of the course since we were last there. Overall I expect my new 2000cc run to be faster again, but it’s nice to see our progression.