Two models are offered for each body style—the 128i and the 135i—and both are available with either a six-speed manual or an automatic gearbox. The main difference between the two models is the engine; the 128i uses a non-turbo 230-horsepower version of the 3.0-liter inline six-cylinder, while the 135i provides a more ample 300 hp from its twin-turbo version of the 3.0-liter six.
Road & Track reports that the 135i "has amazing pulling power" and gives "new meaning to the term 'pocket rocket.'" Some reviewers, however, worry that the car's 3,500-pound weight will overwhelm the smaller engine in the 128i model. Despite this, Car and Driver finds the BMW 128i to be "pretty quick, taking an estimated 6.4 seconds for the 0-to-60-mph run equipped with the fluid six-speed manual." For those seeking a serious performance machine, the 135i's twin-turbocharged engine moves the car to 60 mph in less than 5 seconds according to some reviews read by TheCarConnection.com.
With either trim, Edmunds finds that "a six-speed manual is the standard transmission, while a six-speed automatic with manual shift control is optional."
Popular Mechanics notes that for sports cars "the flip side of all that high performance is usually poor fuel economy. Not here: BMW estimates 30 mpg on the highway." The official EPA estimates for the 2010 BMW 1-Series are 18 mpg city and 28 highway for the 128i, while the 135i returns 17 mpg city, 25 highway.
The 2010 BMW 1-Series handles well and steers beautifully, and it feels positively like a sports car. Popular Mechanics notes that on the track, "the steering, typical of BMW, [is] sharp and quick to react." Edmunds says that "body roll is minimal, and overall grip on models fitted with the sport package is superb." ConsumerGuide also praises the 1-Series' performance, claiming that "BMW's legendary handling capability carries over to the 1-Series." They are also surprised to discover that even BMW's "128i convertible with the base suspension and 16-inch tires exhibits little body lean in fast turns."
Stopping power is strong as well. Kelley Blue Book raves about the "huge front brakes that not only slow the small coupe with ease but also look great" on the 135i. The brakes on all trim levels of the 2010 1-Series are exceptional, and they hold up well under extreme conditions.