|There are numerous U.S. 928 S versions:
1981 - 1982 928 with "Competition" package option. Appears as the Euro 928 S model. Body and interior upgrades, ie: front and rear spoilers, Recaro sport seats, padded steering wheel, no body rub strips. U.S. cars still came with the 4.5 liter 219HP engine, to the dismay of enthusiasts lusting after the 300HP Euro S engine. The Competition Group accessory list did include one very important component -- a limited slip differential. Though not officially monikered a 928 S by the factory, enough of the goodies are present for its inclusion here. 1982 base price $38,850.00. (note 1).1983 - 1984 928 S 4.7 liter 16-valve engine. Finally a true S model hits our shores, albeit detuned from Euro specs. Slight increase in displacement brings similiar performance boost to 234HP, although the press and consumers go wild venting years of pent-up frustration. The new four-speed automatic becomes standard equipment and the five-speed manual optional. Other standard equipment includes leather seats, power windows, automatic climate control, heated electric mirrors and a handling package. At 146mph top speed, Porsche boldly claims the 928 S to be "the fastest street legal prouction car sold in the US". 1984 base price $44,000.00. (note 1).
1985 928 S (Series 3) 5.0 liter 32-valve 288HP engine. Monikered the 'US smog-special' by the Euro press and enthusiasts, this car was actually the first to usher in the new 32-valve design, with Porsche maintaining the more powerful 16-valve engine for all other markets. This was, however, a giant leap forward for US enthusiasts. The 5-speed transaxle received improved synchromesh design, improving driveability. Top speed is in excess of 155mph! Base price $44,600.00 (note 1), production: 5,356 (note 2).
1986 928 S with 5.0 liter 32-valve 288HP engine. Another special variation, this time with the new big S4 brakes and ABS standard (check for VIN 1000 or higher). Base price $51,900.00 before optioning (note 1), production 4,617 (note 2).
Table Source: The Porsche Family Tree (Porsche Club of America, Inc.)
(note 1) Illustrated Porsche Buyer's Guide, (note 2) Porsche Power, Performance, and Perfection