The rise of luxury SUVs meant that an upscale version of the new Ford Expedition was needed. The Lincoln Navigator was at one time the most profitable vehicle in the industry and led a sales upswing that took Lincoln sales ahead of Cadillac for the first time in its history in 1998. The Navigator is the only model that was not changed to Lincoln's new MK nomenclature. The large size and luxurious image has made it a popular alternative to chauffeur-driven sedans. The second generation switched to all independent suspension and later added an L model to compete with the Escalade ESV. Lincoln Navigator parts like the air to coil spring conversion kit are in high demand.