Mazda redesigned its popular two-door sports car for 2006, but retained four-cylinder power and the general design that had helped make Miata the best-selling two-passenger convertible in the world. The U.S. version of this third-generation Miata adopted the MX-5 model name, as used on the car in other markets since its 1990 introduction. Compared to the 1999-2005 Miata, the rear-wheel-drive MX-5 was longer by 2.5 inches in wheelbase and 1.6 inches overall, and was 1.7 inches wider. Base curb weight increased by about 50 pounds. Sole engine remained a four-cylinder, but it was a 170 horsepower, 2.0-liter, in place of a 1.8-liter that produced 142 horsepower. MX-5 came in six models: Club Spec, base, Touring, Sport, Grand Touring, and 3rd-Generation Limited. A manual transmission was standard: five-speed on Club Spec, base, and Touring, but six-speed on the others. Optional on Touring, Sport, and Grand Touring models was a six-speed automatic transmission with steering-wheel shift paddles; Miata's previous automatic had been a four-speed. Side airbags designed to protect both head and torso were standard; So were antilock four-wheel disc brakes. Traction control, antiskid system, and sport suspension were available. MX-5 came with a manual-folding soft top, with a heated glass rear window; a removable hardtop was optional. Sport, Grand Touring, and 3rd-Generation Limited have 17-inch wheels; others were 16-inch. The 3rd-Generation Limited came with a sport suspension, satellite radio, xenon headlights, and special trim. Mazda had few true competitors for the MX-5, apart from the more costly Honda S2000 and the new Pontiac Solstice--plus its coming-soon 2007 counterpart, the new Saturn Sky.