Questions about ZAS and Chiptuning

Good day, everyone! I’m new here in the forum for 5 min… I bought a S500 with ZAS 3 weeks ago… according to my researches in the inet it should be more often to problems with it as well as some threads show. also I heard that the system is paralyzed in the frame of an update at the stardiagnosis anyway. wanted to ask what is there, or. if there is actually the possibility to switch off zas??? a second question refers to the following: before hatt e i a w210 E430 of the 500 comes to me a bit sluggish… a tuner from Cologne, sport-wheels offers a chiptuning with 20Ps extra power and Vmax 262… what do you think..recommendable or negligent? look forward to helpful answers… thanks you in advance greeting from Bonn Ricardo