is there a difference in the VIN that indicates whether it is s1 or s2?
Yes you could tell by the Vin the 6th Letter would be F G or H
(F-1986 G-1987 H-1988)
Also on one of the complance plates would have Built: "MONTH". "YEAR"
the turn from S1-S2 happend some time mid-late 1987 tho not alot of people know when it really happend due to they didnt bring all these changes in in one big hit they happend over months
heres the major diff between the two
this is wat s2 has diff
Interor:
padded glove box
solid headrest
seat rails are able to be unbolted
velour had a better design
dash cluster was black (every other model had the blue square lines)
Buttons were put on seats
vents for the heater were colour coded to the dash
centre console was velour where s1 was leather type
Engine:
was built ready for a turbo
the belt for the alternator was smaller (first of some s2 had the s1 belts but from i think march 1987 they changed to the smaller ones)
power steering pipe was run differant and gave better responce
Pwr steering pump same brand just made diff
Alternater (most fitted with bosch but some had hitachi wasnt just for the calais model)