I have noticed that when you mash the gas from a stop, the car automatically redlines before it shifts. So i'm wondering is there a difference between letting the engine do the shifting or you do the shifting? Is it bad to take it over the redline?

 

From what I understand, on the coupe (but not on some other Mercedes' models) the Touchshift automatic computer will NOT let you go past redline even in touchshift mode. i.e. it'll automatically change for you if the RPM gets too high.

Update, I just noticed you got a C240. That's a whole nother ball game. I don't think the C240 does automatically change at redline. So yes, it is obviously damaging to NOT shift at redline if you have it on Touchshift mode. That's very obvious You'll blow the engine!