Tells me that at 4500 the 9/11 is at least a couple hundred rpm tighter, which to me is a good thing. So, the boost vs rpm up to 3800 are the same, so spoolup and launch should be similar, but over 4500 the 9/11 is more efficient since it slips less so your midrange should be stronger. Top end will probably be about the same (rpm at 100 mph with identical tires, for example), since that's so far over the stall that neither should be slipping, assuming no lockup in either case.