Yes, the ZXR400 is a bit of a weapon. However, I reckon that I used to be reasonably handy round the local Bira circuit and I couldn't get the boiler within a second of the NSR. It was fast for sure, but not as nimble as the lightweight stroker.

1:07.3 on NSR250 SS spec (like F3). Surface not too good, very bumpy.
1:07.0 on NSR250 SP. Resurfaced.
1:08.1 on ZXR400 F3 spec.

As comparison:

1:07.0 on '99 R6, 600 Stocksport. Easy. Then fell off
1:06.5 on '98 R1, 160hp missile. Push it round corners, darkies down straights