Quote Originally Posted by AdamD View Post
... one poster on the forums here has suggested that, once you've got your foot on the brake and accelerator and are ready to make your launch, you can press the ESP button again to re-enable traction control. This then gives you quite possibly the fastest launch.
In theory, I doubt it. Because TCS reduces drive power by using two strategies. 1.EDL - Brake application and 2.Torque reduction. Either of which will slow you down. For an average to poor driver this would possibly give the fastest launch. But a good driver should be able to modulate the pedal to a poofteenth less than where TCS would intervene (had it been on), avoid the torque reduction and thus maximise available torque at the wheels.

If I understand correctly, it is only the engine management system intervention (2. above) that you can disable with the TCS/ESP button. The EDL part will still intervene regardless. By turning the TCS button off you are telling the system not to intervene via the engine management system to reduce torque. This ties in with what Coreying said about how you need TCS/ESP off to enable launch control and that you may still need to modulate torque because the sytem will not do it for you.
There are 4 or 5 ways the system can achieve this torque reduction depending on your vehicle. throttle, IGN, Injection, gear change suppression. None of them will occur with Launch control ON though.

As alway happy to be corrected.