Originally Posted by PNA
It seems to me if you leave it in first -- while she'll keep pulling, at some point in the rpm range she's gonna max out / red line and accelleration will be limited due to gearing. If you doing the quarter mile, maybe the gearing supports it, but I'd certainly like to hear from some other forum members on there approaches at the track first. (PS. If you are in manual mode and have the car in 1st -- I think W mode is over-ridden anyway.)Good luck with your times.
PNA, It's my understanding that it's impossible to fool the Mercedes "automatic" transmission, and make it do anything that will harm it. Thus by putting it in 1st. gear and leaving it there, all it's going to do is stay in that gear until you reach an optimal RPM, then it will "automatically" shift into the next gear and do the same thing as long as you have the gas peddal firmly planted on the floor, no matter what.
I drive a 6 spd. (and I don't drag race anymore either) so as you suggested, maybe some SRT "drag racers" should chime in here and give the best possible advice on exactly what should be done.