Imperial model year ever: 37,593 were produced; the more commonly available Cadillac sold over 120,000 cars in 1957. Cadillac was shocked by the new popular design from Chrysler. Cadillac retaliated by implementing training to its sales force to call Imperial a "Chrysler Imperial" to try to dampen the sales of its competitor. This tactic was to create the thought that you were buying an over priced Chrysler. Quality control also slipped considerably, a consequence of the second total redesign in two years. Failing torsion-bars that were made incorrectly was also a problem from being produced too quickly. Starting in the 1957 model year, Imperials were available in three levels of trim: standard Imperial Custom, mid-range Imperial Crown, and the new top-of-the-line Imperial LeBaron (a reference to LeBaron, Carrossiers). The custom-built Imperial Crown limousine was also offered. Through the late 1950s and into the early 1960s styling would continue to become "Longer, Lower, Wider", with the addition of some of the wildest fins on a car. The "FliteSweep Deck Lid", a simulated Continental tire bulge, was an option for 1957 through 1961 and again in 1963 (due to demand). It was shared with contemporary Mopars, including the Valiant. Exner's design extended to early-fifties concept cars like the 1953 Chrysler D'Elegance. 1958 (Series LY1-L,M,H) Styling changes for 1958 were limited to the front grille and bumper. Quad headlights became standard. The 1958 Imperial is credited with the introduction of cruise control, which was called "Auto-Pilot", and was available on the Imperial, and on Chrysler New Yorker, 300, Saratoga and Windsor models. Power door locks were another new option. Sales slipped to 16,133 in a recession year. Dealers were frustrated with buyers referring to the cars as a "Chrysler Imperial", which impacted sales as Imperial was not seen as having Cadillac's or Lincoln's prestige. It didn't help that Imperial continued to be sold at Chrysler dealerships, instead of standalone dealers, although it did have a separate "Imperial" dealership sign. 1959 (Series MY1-L,M,H) Production was moved from the traditional Jefferson Avenue Assembly plant in Detroit to an exclusive facility on Warren Avenue, north of the Jefferson Avenue factory. Other than a toothy new grill and revisions to side trim little changed in terms of exterior styling for the 1959 model year. A new option was the "Silvercrest" roof which featured a stainless steel front with a rear canopy that could be ordered either in