I felt safe enough with the roll bar actually. I was really noncommittal on making this a full blown race car or making it a half assed race car. Im actually happier i have the 5lb bottle of halon next to me lol.
You really need to figure out how to get on the HPD team for the 25 hours of thunderhill man! Honda has one of the best camps there.
NT01s. Theres a lot of things that go into grip of a tire that ive gathered over the last few years while working at a race shop.
1. heat cycles effect the grip. Tires can only go from hot to cold so many times, and max temp also affects this.
2. storage of the tire - tires typically shouldnt be stored in cold places for long periods of time. I tend do keep my race tires in my office.
3. tires you drive on every day dont make good track tires (refer to #1).
4. weather and UV index / track temp have things to do with grip
5. all tracks react differently to tires - Buttonwillow typically gets greasy after lunch and Buttonwillow isnt great for sticker tires. We found the track is faster on 1 heat cycled tires where as thunderhill is fastest on stickers.
You would gain a lot of time if you committed to throttle before each apex. You seem like you want to throttle on before apex but then you feather it for some reason. Also you can wide open through bus stop. It'll feel weird and may slide a little but there's a lot of track. Your entry to Riverside is too early. Hang a wide line a little longer and gradually turn in. Your current line is what I used to do and it causes you to push out towards the left side dirt which kills speed. That's what I'd work on for now if I were you