It will be a hunt to find parts for them. Similarly it could be difficult to find parts for a Belta but it will be much better than the latter two.
The E140 is honestly an amazing vehicle, the E140 has a bit of a floaty suspension which makes high speed driving feel like you're less in control.
Out of all the vehicles you will probably be able to get the Saga as the cleanest car. Car itself is great, no issues, but you will struggle with the parts support, which will make selling it in the future even harder.
Belta is a decent car. I've had both 1.0 and 1.3 and personally enjoyed the 1.0 liter more for some odd reason. Supposedly they have great fuel economy but I never got much out of the ones we owned (office cars).
