I looked into turbo costs about 18 months ago, IIRC a replacement was about £400, think that was exchange.
I had visited the turbo technics site and spoke to them.
Theres a trade supplying demand for refurbished Turbos, like I posted earlier, one has only to consider that cost against the value to them of the car, and whether anything else costly might fail soon.
You don't want it turning into a money-pit, obviously 😉
Chain drive for the cam was one of the largest factors in deciding to get my first MK2 mondeo Diesel, and that was about 5 years ago, haven't looked back since.
I just change the oil regularly, and fix whatever needs fixing, when it needs it, but with my latest one, nothing really changes, I just refuel it and keep driving.
Ford test for 150K, so after that, you're on your own, but steer a sensible course, and they're good.
177K in my last one, 180K plus with the current one.
🙂