My TVR speed 12 I find is very quick, the issue with this is the start, managing the start is impossible on this as it will spin up to 4th with S3 tyres. I find with it max'd out and lightened, putting ballast on the back increases the PP further and increases available traction, full revs and pull of in 3rd & no tcs, still not as quick as say a veyron or tuned skyline of the mark but once going is very quick, also there are no gear changes up to 120-130. I find speed 12 gear changes in 1-2-3 are slow starting in 3rd clears these.
I find that setup quicker than other methods I have tried and quicker than over speed 12 i have dragged.
I have tried adjusting the gearing to say tgtt but as it can spin through all gears up to 4th, gearing makes little difference and it only get up to 5th maybe a little of 6th anyway, tcs bogs it down.