The 2013 BMW 1-Series remains available in two main versions: the 128i and the 135i. With the 1-Series M Coupe now out of the mix, 2013 brings a model that channels some--but not quite all--of that performance goodness: the 135is.
BMW 128i models are powered by a 3.0-liter normally-aspirated inline six-cylinder rated at 230 horsepower, while the 135is borrows the same engine that's found in the 335i, delivering 300 horsepower and 300 pound-feet of torque. All 1-Series models are rear-wheel drive, available with a choice of six-speed manual or six-speed Steptronic automatic transmission (128i) or seven-speed dual-clutch transmission (135i).
The 135is gets a stronger version of the engine, making 320 hp and 317 lb-ft. It includes special programming for the stability control system; and a new differential in the 135is offers cooler operating temperatures and, in theory, somewhat greater efficiency in power delivery. It does this by using new double-helical ball bearings, reducing friction and the amount of lubricant needed within the differential. The 135is still doesn't get a true mechanical limited-slip differential like that found in the 1-Series M Coupe, however, instead relying on the familiar brake-based simulated differential lock to improve acceleration and low-traction grip.
The 135is accelerates briskly; the 0-60 mph sprint takes just 5.3 second when optioned with the 7-speed dual-clutch. An optional M Sport package enhances things even further with its stiffer suspension calibration, improved aerodynamics, and upsized wheels with sportier tires.
On the road, the 1-Series impresses, handling with poise and balance, a noticeable but hardly excessive level of body roll, excellent overall grip, and ready acceleration. Enthusiasts will relish in a stability and traction managment system that is not overly invasive and allows for fairly aggressive driving without intervening too much.
Braking is an especially strong suit. It's stable and straight, although track duty can cause heat soak and fade unless you upgrade the street-oriented brakes.