Are you? your car is under warranty. no?
That said, if I had a brand new car I couldn't use for 3 months I would be asking for my money back and getting another car.
Even if the part is the same, if an entire batch is bad, then every car made with that batch will have to have the module replaced and the factory won't be able to build new ones. To Mercedes, keeping the factory running will be the priority, so the first 'good' ones will go to build new cars and only once the supplier has caught up with production demand will they be able to supply spares for cars with defective modules.I thought the whole point of keeping model runs 'similar' was so that the 'basic' parts for the entire model range (R172 in this case) could be more or less interchangeable. Are they telling you that the brake module for the 2016 SLK is different from the earlier R172 versions (from 2012, I think)? I would find it hard to believe that they redesigned the module between any of those model years - especially since they are discontinuing the R172 Model this year. (Maybe someone with a Startek login can compare the part number between a couple of years to see if they are different). If that was the case, I would think that they would only do a redesign if there was a problem with the previous years' design. I call BS on this and would be raising Holy H3ll if that was my car. Are they going to extend your warranty and make your payments? Have they given you a better car to drive? Have them remove the module from a new SLK and make THEM wait for the part before they can sell THEIR car. GRRRR......