Measuring downforce in F1 cars as a torque, but as a linear load for NASCAR?
I'd love to have a go. Doesn't scare me, wet or dry, in the slightest.
So a NEXTEL makes 2000lbs of downforce. Plus it weighs 3500lbs. So on a level track it will effectively weighs 5500lbs.
An F1 car makes about 2000lbs of downforce, but only weights about 1200lbs, so on a level tracks effectively weighs 3200lbs.
Banking increases downforce and reduces lateral tyre loads.
A NEXTEL/NASCAR/STOCKCAR should and could run in any weather F1 can run in. The only arguments are that the cars are too fast (why don't they slow down in the wet?), the spectators can't see (oh noes!) and pile-ups might not be visible early enough (flags/spotter/radio/slowing down).
I'm not sure you are at all right on the sidewall/slip angle stuff. I'm not saying they can get away with lots of yaw, but grip, no grip isn't correct at all.
A combined 4G? Is that the vector of 3 axis acceleration? How much braking/accelerating do they pull mid corner? The banking will reduce the lateral acceleration (as reported by a datalogger orientated horizontally when the car is on level ground), but increase the vertical acclerations. If they can make a dry tyre that works at 4g, I'm sure they can make a wet tyre that works at 2 or 3.