I use the autoclutch almost on every car except the Mini Cooper S. But if you trailbrake a little during downshifting in for instance the beemer, you slow down much more then with the clutch off i think. Wasnt it Greger Huttu that did that during his first rounds of our league?
In real WTCC they only use the clutch during the start. The only one i believe that uses the clutch during real racing is Jorg Müller (freaking heal and too action

).
Whaha and here is a wannabee that thinks he can do the technique lol (special attention for the shoes, this one must be from outta space)
This is a nice example of what i wrote, the driver doesnt use the clutch at all gearchances: