I offer my condolences on losing your Benz and having to downgrade to a poorly kept example of an already "iffy" model. In fairness to the Renault, I would imagine that it would be insanely difficult to go from something as fine as a Mercedes to anything less. I have a BMW, so I can see why you are upset as I would have difficulty adjusting too. Good luck in your quest for another Benz, or whatever.
196,975 miles. WOW. I'm surprised it managed that many. Mine was going wrong at 80,000. I don't think you can complain at it going wrong with it being 20 years old and that many miles.
I do not think 5's were designed to last more than 100 thousand miles at the most. At least in the USA anyway. We had three, an '80 base model. an '81 Le Car Deluxe with sunroof, and a 1982 5 door Deluxe. The 1980 was the most reliable but also the one with no options. It had one problem while we owned it. a broken torsion bar. The 81 had cooling problems and by the time it was six year old had many problems. Head lights, fuses, brakes, steering and rust. The 82 also had cooling problems and a blown head gasket. The dealer said the cooling system was poorly designed. They were not designed to travel the long distances at the high speeds we drive.
I owned a 1980 R5 TL, and I still own a 1986 R5 GTL sport with 1397 cc engines and 4 speed manual transmissions. They are very reliable and good on gas.
Parts are hard to find now as there's fewer R5 donor cars around. New wear and tear parts can still be purchased from an auto parts store, and they're cheap compared to German or Swedish car parts.
Old car problems come from lack of maintenance and age. Head gaskets on any car will blow if the engine overheats and you don't pull over and let it cool down. It's cheaper to upgrade to a larger radiator when you have a cooling system problem. Check for oil leaks and have your car rust proofed.
Overall the R5 is a better car to buy than British or Italian economy or sports cars from the same era. Buy a repair manual because they're easy to work on and will last a long time. The guy I bought the 1980 from had 675,000 km's on his other R5 that he used for commuting to work.