Well Eric...I learned something new (thought I was the three pointed star king..laughing) I did not realize that some of the '70s vintage Benzes had this feature. The Orthopedic seats I have seen on W126s (uber rare) were power sandwiched between the seat and the center console, pic below:
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I have never seen a W116 six-niner with "pump" lumbar seats
Thinking back yes 1982 is the correct year for the Celica GT-S \ Supra GT-S and the lumbar hand pump.
Back on topic, to keep a 930 paced with a Viper (and any turbo car for that matter), you need to be well into the power band, turbo boiling, cruising at 60mp/h in 5th requires a gear drop (or two!) to be matched to a V10 big displacement all aluminum high compression normally aspirated muscle car.