As I see it, the "issue" is with the moving time frame for belt changes. Depending on the year, the change schedule seems to be anywhere from 35k, to 45k, to 70k just to name a few of the numbers I have seen posted on this forum. Happily, the mileage increases with the newer models thereby convincing me the engineers at Volvo were doing what they did with the "red blocks", improving them incrementally. Unfortunately, the 960 engine does not have the benefit of decades of improvements behind it. Were the model still in production, I am sure it would continue to be tinkered with by the designers to increase it's longevity. Such is not the case and the newer (compared to the "red block") design 6 cyl., IMHO, just does not have the pedigree.

I'll recommend a proven design at the pinnacle of it's life cycle before a newer, less proven, engine.