From my readings the spit had a very high top speed in a dive compared to most planes, excluding the mk1 which became hard to control due to fabric on the control surfaces billowing at high speeds.
From Eric Brown, _Wings of the Luftwaffe_, and various NACA reports:
Spitfire: "maximum safe" .83, terminal velocity dive ~ .86 [M=.92 in an uncontrolled dive] Me 262: "tactical" .82, "maximum safe" .83-.84 Ar 234: "tactical" .75
Meteor I: pitchup above M = .80
P-51B: drag divergence M = .67
Vampire: .74
P-47: .69
F2FA-2: .66
P-39: .675
TS