There is something I am not very clear, you said disabling the air pump may cause CAT premature failure, but all cars I have had other than Mercedes don't have this kind of air pump, and they all use catalytic converters and O2 sensors.
Or do you mean with this air pump catalytic converters and O2 sensors on MBs last longer than those on Cars without it? My Ford doesn't have air pump, but being a key emission component, catalytic converter is covered by 8 year 120K Km warranty, that sounds long enough for me.
99 BMW 540i 6-speed 110K Km
03 SAAB 9-5 wagon 80K Km
92 400E (Sold) 245K km
Still missing the days with the Benz, it kept me busy.