Andrew
You need to go back to before you were on the scene as an owner for the really fast terminals, all set by Tony Marsh with his highly tuned GTD Mk11. However do note that he has always run on street rubber ie 17 inch Pirelli P Zero's, which makes the times and terminals even more impressive.
In 1995 Tony's times were 12.45 in practice, 12.30 with 137 mph terminal and then 12.29 and 134 mph in the timed runs. They do not record terminals for practice but I recollect it being 139 but stand to be corrected. Hence use of wording "up to 140" before.
In that year Justin Bell in a road going Viper did 12.48 in practice, 12.33 with 118 mph and then 12.39 with 118 mph again. His practice time may have been quicker if he hadn't burnt rubber way down the track!
For comparative times, I see a Porsche 911 SC 3 litre did 14.76 with 100 mph. Ferrari Testarossa did 13.27 with 114 mph. Genuine AC Cobra (289) did 14.05 with 104 mph.
In 2000 Tony Marsh posted terminals of 135 and 134 mph, both times in the mid 12's.
The other best times I have recorded are Roy at 12.75 and 12.64, Paul corrected me on the 12.01 to 12.10 but he has done quite a few low 12's now, and Robin at 12.79 and 12.93.
For interest sake my best time of 12.61 (not 12.63!)was in 1993 but with a terminal of only 111 mph.
If you averaged out all the times our club has from over the years it would make depressing reading. My records show many 14 second runs and slower ones as well.
Malcolm