attached is bulletin on balance shaft. i bought my 2006 ml350 with 83k miles. right after i got it i had one camshaft sensor go out, and a week later another. i luckily do not have the balance shaft problem. my point is this: not every problem indicates the balance shaft problem. the cam sensors,of which there are 4, do go out. no big deal. and my other point is that not everyone that is in vin range to possibly have the balance shaft problem has the problem. when i spoke to mbusa they indicated that if i did have the problem down the road the likely would work something out with me thru the dealer. i believe her as indicated by this thread with someone saying mb will pay half. i say take them up on that offer and pay the $2k. then other then minor electronics your basic engine will be solid and good for ten if not 100 of thousands of miles. cel light can be scary but can be any number of things. i had intermittant misfires turning on the light. i disconnected and reconnected coils and light has not gone on for weeks.
taking car back and forth to dealer, and check engine lights coming on can be both very concerning and a pain in the butt. but that is sometimes how it is with these cars. reading the codes to diagnosis, making tweaks, replacing parts and re-reading codes can be part of process.
you have to decide what is right for you depending on aptitude, time, and money. i paid $80 to mbusa and bought shop manual. i also paid like $120 and bought my own code reader. i also signed up for epc on line so i can figure out what part# i need and then shop myself from many online oem mbdealers.
0016 and 0017, i think are crankshaft position sensors. i had to replace this item on wifes ml320 2001. it was 30 minute job and like 80 bucks. i don't think this has anything to do with balance shaft issue. eventually the wifes car would not restart when hot. so i would get it fixed.
the other advice i have is negotiate. when i needed to have something repaired at dealer and labor was small but part was expensive. they matched part price from online mb oem dealer. for example, i don't know exactly what air pump you needed but the link i gave you has $750 retail air pump for $585.