NT01 is probably the best value for HPDEs. They can get pretty hot, recover quickly, and don't degrade with heat cycles like the R6 or R888. They will last about twice as long as an R6 on the E46 (based on 15 sets of R6s on my E46 and 5 sets of NT01s)
On the heavy E9X, if you're driving at 9/10ths or above where you are getting the benefit out of the tire, I'd be surprised if R6s last more than 1 to 2 HPDE days. I got about 4 hard days out of two sets of NT01s on my E90.
I'd like to try the R1s soon....sounds like an awesome tire.
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