Daniel, in a previous mail you said the auto trans had been repaired. Any idea of what went wrong? Or was it the usual case of overly stressed total trans replacement or a lost tooth off the crown wheel or pinion?
Putting steamroller tyres on will only increase the likelihood of damage happening to the auto. The reason why there would be so many BTCC lookalike 19's OS would be because mostly would they are 16V manual trans cars. 19 Auto's would be in the minority. Contrary to what people may think I provide info in good faith, not to get at people or put others down. As several correspondents have said, it is your car do what you want to it.
People have told me that the gearbox in my 4 would blow up from being used in a rally. It is still in one piece, but I do know that they are also prone to loose crownwheels, fortunately it has not happened to my car! One thing in favour of stock cars is their stealth ability, many years ago after an RCCSA (an indicator of how long ago!) meeting, a friend and I drew up at the lights against a modified VW Beetle and a VW 412 wagon (1.7 injection). We set off from the lights in a brisk manner, and I managed to beat both cars in a quick traffic light GP. They turned off later so we went back and found both cars, they could not believe the 12 was stock, and that it had beaten their IDA'd 1600 VW Beetle, let alone the 412. It just increased my respect for the old Sierra motor! Mind you I'd never try the same thing with an Auto trans!