Alec, you beat me to it ! That should have been answer number one to the OP's question, we on the forum are slipping a bit, I blame Covid/lockdown/Brexit/Boris/Greta/Elvis....
OP, I have a S203 C class 2006 estate it's a C55 AMG so
very different to what you are looking for ..but they are the same size on the inside and they are quite a small car inside (even the estate) version . You mention comfort in your post and immediately someone mentions an E class instead of a C class, and that would be correct if you can put up with a physically bigger car for comfort the E class will be better than a C class.
The interior space is something I’d forgotten, being over 5 years since I traded mine on , but now I remember, coming to it out of a 500SEL , I did find it quite ‘compact’ inside .
As with my three 190Es , I found space in the front ‘adequate’ but the back seat not a place I would wish to sit long as an adult , though plenty of room for smaller children.
In retrospect, I made a mistake with the car I bought : a C270CDI estate , in Avantgarde spec . I was attracted to the car because everyone said the 270 was a great engine , the car had a good spec and as a bonus came with a Brink detachable towbar.
The one thing I came to realise after getting it ; the first car I’d had in years without a sunroof, and a black car with black interior was that it was positively claustrophobic inside ( again I perhaps felt it more than most coming out of an S class , but the idea was to get something cheap to run after 5 years covering over 100K in a 5 litre V8 .
The C270 did return 50-55mpg , never worse than 46 on the computer , but I sank thousands , almost as much as I paid for the car , into repairs , almost all on the Diesel engine , before getting another 190 and my R129 .
I have to say that my 03 reg car , late pre facelift car was rust free , although I could see where one rear wheelarch had been painted badly ( perhaps accident damage ) and the whole car felt very solid and well made .
Beside the three issues I mentioned in my earlier post : locks , keys and one control arm ; and my numerous issues with the Diesel engine ( all 5 injectors needing changed , thermostat ,high pressure fuel lines and turbo air pipe ; the turbo also failed in the hands of the next owner ) , the only other thing was failure of the tailgate wiper , which won’t be relevant to the OP , who is looking for a saloon .
I’d agree that if space and comfort are important to the OP , then it would be worth looking at an E Class of similar age , W211s are quite well thought of and prices are similar to the W203 range . It isn’t a hugely bigger car on the road , nor for similar engines would I expect running costs to be much different.
What I would say to the OP is that all these cars are a few years old now , and while there are plenty of nice ones still around , they are premium cars which came with lots of toys and gadgets - do make sure that EVERYTHING works - on cars that are 15-20 years old it is common for air conditioning not to be working , don’t be fobbed off with it just needs a regas’ , sure , it might , but it equally might need a new condenser , or some other expensive repair , similarly check cruise control , electric windows , sunroof , electric and heated seats - all these things can cost to repair . Also make sure you get two working keys with the car - new keys are well over £200 just to buy , then you have to pay to get them coded to the car - make sure each key locks , unlocks , opens the boot and starts the car - keys can be fragile , and again don’t be fobbed off with it just needs batteries’ , the batteries are only a couple of pounds so why wouldn’t a seller have put them in ?
When I bought my car , it had a skinny ‘space saver’ spare - there is room in the boot for a full size wheel - because I do big mileages it was one of the first things I changed - a brand new steel spare wheel was only £50 from the dealer , and I was putting five new tyres on anyway .
On the subject of tyres - you can tell a lot about a car by looking at the tyres - look for uneven wear , which can indicate suspension wear or misalignment. Also look at the kind of tyres fitted - these were expensive cars new and a caring owner will have fitted decent tyres of a premium brand - is it sitting on a matching set of Continentals or Michelins , or is it sitting on a mish mash of makes you’ve never heard of , with no two tyres the same make ? I admit I have in the past replaced tyres in pairs rather than all four ( or five ) at once ( do check for a decent spare , and that the jack and toolkit are present ) but my minimum standard will always be a matching pair of decent tyres on each axle . I will sometimes run four premium tyres on the road wheels , and if tight for cash put a budget tyre on the spare - especially where it is a steel spare that won’t be kept on the car longer than necessary when the other three wheels are alloys .
Besides the above it is the same as any other used car - look for some service history to check it has been cared for - depending on mileage , look for evidence the automatic gearbox was serviced on time - if buying privately , look at the seller and his home : the old saying that ‘nice cars come from nice people’ is still true - if the car is on the drive of a tidy , well cared for house with neat tidy gardens, it points to an owner who is likely to have cared for his car the same way ; if the seller in unkempt and in an untidy , neglected house , has the car been looked after ?
Good luck
Condition and service is important.
