For 2004, a retractable-hardtop two-seater was Cadillac's new entry in the luxury-roadster field. Cadillac's last previous two-passenger convertible had been the 1989-93 Allante. The new rear-wheel-drive XLR competed with such open-roofed cars as the Lexus SC 430, Jaguar XK8, and Mercedes-Benz SL500. Though greater in wheelbase and width than those rivals, the XLR was shorter overall, lower, and slightly lighter. Its chassis structure and composite plastic body panels were similar to those used by the Chevrolet Corvette. However, XLR had its own styling inside and out, a power-retractable hardtop instead of a cloth convertible top, a suspension tuned for luxury-grade ride and handling, and a different V8 engine. That engine was Cadillac's 4.6-liter Northstar, here tuned for 320 horsepower. The sole transmission was a five-speed automatic with manual shift gate. A traction/antiskid control was standard. So was GM's Magnetic Ride Control, which automatically adjusted suspension firmness based on the road surface. Also included was adaptive cruise control, designed to maintain a set following distance. Tires were 18-inch run-flats; no spare was included. Every XLR came with heated and cooled leather seats, wood interior trim, and front side airbags designed to protect the torso and head. A 7-inch dashboard screen projected navigation and audio functions, and played entertainment DVDs (only with the transmission in Park). Also standard was Cadillac's Keyless Access, which let the driver start the car and operate the locks and trunklid without removing the keyfob from pocket or purse. Satellite radio was the only option.