The US Spec E28 M5 ended up being a very different car than the Euro Spec. The US Spec was only available for one year, 1988, and only with a black exterior and tan interior (apparently there are a few black interior US Specs floating around, although they are very rare). The US Spec did have the same M88/3 engine (a.k.a. the S38 and the M88... it was the same engine that was in the E24 M635CSi, E26 M1, and South African E23 745i); however, it was equipped with a catalytic converter, unlike its European counterpart. This restricted the M88/3 to 256hp and 243lb-ft of torque. Other differences include the 300-some-odd pounds of fat that the US Spec gained, the half-inch taller body, the longer final drive ratio, different headers, different ECU, lower compression ratio, and a single row timing chain (as opposed to a double row). These all made for a much less exciting sport sedan in the US. It is no wonder that American BMW Motorsport enthusiasts have gone to such lengths as to import European E28 M5s. The advantages to having the Euro Spec as an enthusiast and tuner are endless.