Audi RS4 and R8 peak power is 420ps @ 7800rpm, RED LINE 8250rpm. (difference 450rpm)
Mercedes C63 peak power is 457ps @ 6800rpm, RED LINE 7200rpm. (difference 400rpm)
BMW M3 peak power is 420ps @ 8300rpm, RED LINE 8400rpm. (difference 100rpm)
BMW M5 peak power is 507ps @ 7750rpm, RED LINE 8???rpm (difference ???rpm) please fill in the blanks.
Working on the opinion that maximum revs is the ideal point of shifting in all of these cars is wrong, peak power revs is the point, nothing before it and nothing after. Whether is would make that much of a difference to your findings I don't know but I thought I should correct the point in question.