Oddly, while 8,250rpm is indeed bonkers, it's as smooth as 6,500rpm was in stage 2 form I'm already very comfortable winding out Monty's Duratec to 8k and beyond, this when 7k was the end of the world before.
Monty seems to enjoy it too, but he'll never pass the 100DB noise test at Castle Combe without his DB killer.