I own a 2011 S212 E220 CDI SE Estate currently circa 145k miles. Some on here have seen it...IMO it is presentable for age and mileage but I keep on top of things. FMBSH by 1st keeper...(work elsewhere when owned by me).
Mine had a new warrantied engine at around 40k (1st keeper hit a deep puddle). I find the engine & performance ample. An E250CDI I drove not significantly more urgent albeit a bit bit more going on. E350 CDI arguably the drivers diesel weapon of choice if numbers stack.
In 1st year since owning mine i have caused mine to have replacement rear brake lines & fluid, 2 rear suspension airbags, tyres, service + filters, exhaust clamp, bonnet release, battery, a rear top mount, tints, cosmetic tidying & sundry items. That lot stacks up , (north of £2k), My car is well cared for. Like plenty on here....I am fussy.
The money mentioned should get into an honest higher mileage S212 with history. Do put aside contingency funds to sort stuff.
S211 a fine vehicle. I have driven an E220CDI - ample power IMO for sensible driving.
Many prefer it & the styling. I personally would go for a face-lift model due to various improvements. I would look at the E320CDI if buying an S211 ..maybe a Brabus chipped one if able to find a genuine one. Don't dismiss lower powered models. The E280 CDI more than ample for most..some say smoother & better mpg than E320CDI.
Others may have more to add or have alternative views. Feel free to ask me, (or more experienced owners) , if you have any questions.
HTH