I have a c63s amg coupe edition 1. My local dealer put a renntech tune and BMC filter on my car when I purchased it. All factory warranty retained. But that’s the only company they deal with. Night and day difference in the car.I’m assuming a tune voids the powertrain warranty on that car? I wouldn’t want to be the unlucky bastard that blows one of those up, has to be pricey to fix out of pocket