any tech differences between S320 and S320V?

No, not at all. Basically it is just the longer wheelbase with all the extra space given to the rear quarters.

Only noticeable feature would be the longer rear doors on the S320V.

Some markets (I don't know about the U.S.) would add certain optinal equipment as standard in their long-wheel base models. But this is just an add on commercial strategy. (For example the rear electric sunshade).

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A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]