Dunno know about the S70 (as opposed to the V70), but Nivomats were very definitely available as an option on the 2WD V70 when I ordered my car.

(When the salesperson asked if I wanted to order them, I was horrified at the thought, and reflexively clutched my wallet!)

A factory HD suspension was also an option in '98 (but not '99), and I ordered that, but my car ain't got no Nivomats!

-BTC

'98 V70 T5 5-speed, 166k mi, front IPD stabilizer bar, rear factory HD bar, Bilstein HD, Volvo strut tower brace and skidplate, e-codes, V-1, Mobil-1 since new, Michelin X-Ice on steelies

"The major difference between a thing that might go wrong and a thing that cannot possibly go wrong is that when a thing that cannot possibly go wrong goes wrong it usually turns out to be impossible to get at or repair." -- Douglas Noel Adams (1952-2001)