The third generation Mustang had two different front end styles. From 1979 to 1986 the car had an angled back front clip and four headlights, known by enthusiasts as "Four Eyes." Then in the 1987 to 1993 model years, the front clip had a rounded-off shape known as the "aero" style with flush composite headlamps. Also in 1986, engines featured EFI (electronic fuel injection) instead of carburetors. Other changes for the 1986 models included an upgraded 8.8-inch (224 mm) rear-end with four shock absorbers. In response to slumping sales and escalating fuel prices during the early 1980s, a new Mustang was in development. It was to be a variant of the Mazda MX-6 assembled at AutoAlliance International in Flat Rock, Michigan. Enthusiasts wrote to Ford objecting to the proposed change to a front-wheel drive, Japanese-designed Mustang without a V8 option. The result was a major facelift of the existing Mustang in 1987, while the MX-6 variant had a last minute name change from Mustang to Probe and released as a 1989 model.