I only tested mine once, on a nice flat piece of ground near a construction site.
less than half tank of gas, and modified as stated in my signature.
I did 6 runs, and they went from a low of 4.8 sec to a high of 5.3 secs. No quarter times.
I also came off the line fast with very little tire spin and hit the shift points pretty well. I would not want to abuse the car like that very many times.

__________________
Just sold my beautiful CS, now the fun begins as I look for its open top replacement...