Helllo,
~183 cm, no problem.

I think (I have to check it) I even do not use the rearest seat position.
Also headrest is fine.

>Außerdem hattei ich den Eindruck, dass ich diese bestmögliche Sitzposition bei umgelegter Rückbank nicht erreichen kann.

That's almost true, (will check it too), seems it is needed to fold rear seats all the way down (push it down, jump on it ;-) ) to get drivers seat to the rearest position.

>lt. ADAC soll diese nur bis 165cm ok sein.
Do not know how ADAC tested this, but think could be their mistype error (and should be 185 cm???)

Martin