Pretty sure
@TaoJones is about to come on this thread and drop the mike.
Funny you should mention.
Engel. Accept no substitutes. One moving part (a swing compressor), very low energy usage, quiet, and a bulletproof reputation.
The 40-quart marine version will fit perfectly aft in a Model S, and can be either a fridge or a freezer, managed to the degree. For bonus points, consider a remote thermometer so that you can see at a glance from the cockpit what the temperature is. Perfect for maintaining medicine for a passenger and/or just for fresh produce and grillables when you want something better than the usual road fare. If you choose the freezer option, it *will* freeze things solid. Including golf ball ice cubes for a proper happy hour, so I've been told.
https://www.westmarine.com/buy/engel--40qt-portable-refrigerator-freezer--11589462
A Model X can easily accommodate the next size(s) up which offer both fridge and freezer compartments.
Buying from West Marine instead of Amazon affords the option of a *walk-in replacement* and extended warranty in the exceedingly unlikely event that your unit fails. No headaches associated with depot shipping to Florida or finding a repair facility.
As long as you're running one 12V supply from the fuse box, consider a pigtail for dual receptacles aft - that way, you can expand yer galley with yer choice of 12VDC appliances (popcorn maker, microwave, crockpot), or an inverter if AC appliances are your thing.
FWIW, my Engel has lasted, so far, over 3 years and right at 100,000 miles and counting.
Well, there ya go. Good luck with yer respective choices.