The 2010 BMW 135i will be powered with the new twin-scroll turbocharged 3.0-L inline-six cylinder engine which is named as N55. The new N55 produces highest output of 300 hp at 5,800 rpm, with peak torque of 300 lb-ft offered all the way from 1,200–5,000 rpm. This is the same level of performance as the current 3.0-liter twin-turbo six-cylinder. Tthe new engine will offer better throttle response and yet added fuel efficiency.

The 2010 BMW 135i will be obtained with an optional 7-speed Double-Clutch Transmission (DCT). It features commited steering wheel paddles for upshifting using right paddle and downshifting using left paddle as well as a console-mounted e-shifter.