I don't think they have different calipers. But they do have different rotors. It is code U28. That gets you 360mm rear rotors. Standard is 340mm. I believe the sport package comes with the U28 code for 360MM rear rotors? But personally I can realize this would mean a different attachment point for the caliper to clear the larger rotor. This could create a clearance issue in the front but not rear?? But 2 members have stated they had issues with 18" rims on a sport package. I don't see 2 different part#'s for calipers just rear rotors.

Well, I do not believe rear rotors have ever been a problem, as they tend to pretty much always be smaller than the front. I guess I wonder why, if upgraded brakes were part of the AMG Line Pkg., MB would not tout them as being included in this very expensive package. Here are screen shots from the MBUSA "Build" sites for both the E & S Class sedans. I know that MBUSA can be dense, but I would really hope they are not stupid, right?

Just as more info, if you are speaking about the codes on the DataMB data sheet from a VIN lookup, I don't have a U28 code. On my 15 S550 with Sport Package and AMG 20" wheel option, the data sheet shows Code 769 AMG 20" Spoked Wheels with Mixed Tires; and Code 772 AMG Styling Package-Front Spoiler, Side Skirt. The only brake related codes are related to the braking features of Distronic Plus.

Thanks. I do have Distronic also. The AMG styling has nothing to do with brakes, it is code 321-sport package and lists nothing about brakes. BUT there are 2 different rear rotors for this car. Base and sport have the same calipers but some have said 18" rims do not fit on the sport package cars???

If there is a problem with 18" wheel fitment--and I still don't think there is--it must be on the front. I just went and looked at my car with 18" wheels and in the rear, there must be 3" or more space between the edge of the rotor and the barrel of the wheel.

Of course it would be the front. Your getting confused with that I said there was no difference in calipers and noted there are 2 rotors for the rear. You could probably put a 16" rim on the rear. That is not the issue I am sure. 18" rims are not offered on any model but the base and maybe there is a reason? As 2 other have said they don't work on the sport package. I don't know whats different. But for those of us considering more sidewall with the sport package it appears 19" is as low as we can go. I too looked at the exact description on my sticker and online for the Sport package and it is clearly cosmetic including rims, pedals, side skirts, front and rear bumpers.

I had 18" stock rims with Pirelli RF on my 2014 S550 and just switched to OEM 20" AMG wheels and non RF PS A/S3+. Ride is fine, just as smooth as the 18" RFs.

Update:

Going on a road trip up north and did a thorough inspection after an oil change. Found a corded, damaged right rear tire! Leaving in less than a week no time for the decided 19" rims, new TPMS and mounting Michelins. I reluctantly and immediately ordered and installed Michelin PSS AS3+. This wasn't the plan but had to be safe for the road trip. Well........I am very impressed with the change. I knew the GY runcraps were bad but this is a huge difference. Changed the whole ride of the car. Running 36 psi presently. Compliant and comfortable. Takes bumps much nicer. Not so harsh as before. Its riding a lot closer to my old W221 w/ 19" rims and Michelins. Driving in the garage on GY runcraps and riding out on 20" Michelins is a very big upgrade in comfort. Obviously I just installed 4 of them so I will be on these for a while. For those in any pothole region I can only imagine more protection on 19" and probably comfort. But in Fla the Michelin AS3 on 20's is pretty nice.

Just swapping out the runcraps will make the most diff, Id say there will be close to no difference w a 19" or a 20". Ive done the swap myself.

Yep! The ride was so harsh with the run craps that I felt the 19" would be the best bet. I am pleasantly surprised at how much of a difference the Non run flat Michelin is in a 20". Looking forward to our trip now.

Did you change from 20"RF to 20" no RF or change to 19" no RF? I am debating i.e. Buying 19" wheels no RF or doing what Seamus did..

Thanks.

I went 19" runcraps to 20" non runcraps.