Its strange the options which are / are not available in Canada vs the USA
In Canada, for my 2012 ML550, heated /cooled cupholders were not available, yet i was able to order 21" AMG wheels , shod with summer rubber.
(i understand the 21" is not avail in the USA...correct ?)
My ML has the display showing individual tire pressures in kps or lbs, to avoid having to use a pressure guage to check them....
Do the 20" AMG wheels in the USA come with this tire pressure readout available ?

Heated/cooled cupholders are not available in conjunction with KEYLESS-GO.

21" wheels include active TPMS (code 475).

Canadian law differs from the US, hence we still use the passive TPMS (calculated based on ABS sensors rather than a tire pressure sensors in each wheel) on most models. In the US, most (if not all?) MBs include active TPMS, regardless of tire size.

In Canada, only the AMGs and a couple of select models (E350C 4MATIC, ML550 with 21s, for example) have active TPMS.

Not sure what you mean by "readout" but my understanding is that TPMS is required on all cars sold in the US and has been at least for a few years.

He means being able to read exact pressures for each tire; US regs only require that TPMS gives a warning that when a tire is low.

We got our ML63 with the 21" wheel option.