Looking like a full-size minivan that shrank in the sun after a trip to the car wash, the 2006 Mazda 5 is a unique six-passenger vehicle seeking to establish a foothold in a niche market. Based on the Mazda 3 platform, the Mazda 5 has all of the roominess of a minivan blended with the size and economy of the Mazda 3. A 157-horsepower, 2.3-liter, four-cylinder engine drives the front wheels through a standard five-speed manual or four-speed automatic with manual shift capability.