The one piece Speedline wheel was introduced in 1993. They are often mistaken for the Stern wheels, as they are similar in appearance. The easiest identifier would be that the Speedlines do not have "Stern" stamped in one spoke. The fronts are 17x7.5 and the rears are 17X8.5. One spoke was ink-stamped "Saleen by Speedline" - a detail that is often missing when the wheels are re-finished. However, not all wheels said Saleen on the outside of the wheels (under the clear coat). Speedline wheels are stamped Italy on the rear on the rear of one spoke. Speedlines are more common than the Sterns. In comparison, there were only a couple of dozen Stern 3 piece sets imported and double that for the one piece Sterns. They imported many more of the Speedlines in both 5-lug for cars and 4-lug for catalog sales.
The Speedline wheel has also been reproduced by Wheel Replicas recently, at a much lower cost than originals.
http://www.saleenclubofamerica.com/SCOATech/87-93.htm