For normal road driving, I think it would probably be more sensible to leave the DSA on, especially in wet weather as the potential benefit from a safety perspective probably outweighs any performance benefit you'll get from switching it off. Out on a track or for 1/4 mile racing, its a totally different matter. From my experience, in those situations, the DSA system takes cuts the power way too early and does not feed it back quick enough so its actually beneficial to drive with it switched off. I did try an adjustable Racelogic traction control system once and that really worked well and was leagues ahead of the way the DSA system worked, but it did cause some issues with injector duty cycle control so I wouldn't really recommend that again.