To avoid confusion: as is convention here at MVS, model years are North-American Volvo models.
Have something to add for 1994 -> 1995 850 changes?
Summary of characteristics for the 1993 850
- all 850s are GLT trim
- no wagon available
- no turbo engine available
- 4-bolt wheel lugs
- 1993-specific wheel covers
- headlights (taller)
- tail lights (taller)
- seat coverings
- timing belt change interval 50k miles
- different spoiler on the sedan
- ABS standard
- Traction control was an option
Summary of characteristics for the 1994 850... assume things are unchanged, except for:
- dropped GLT designation, base 850 is just "850"
- wagon debuts
- turbocharged engine debuts (222hp), available for both wagons and sedans
- new base-level sedan and a Level II tier of optional equipment for both sedans and wagons
- timing belt change interval moved up to 70k miles
Those are the specific differences I know of. If I have anything wrong, I'll update this list.