M division has also dispensed with rear bushings, with the M2's rear axle subframe bolted directly to the structure. (autocar.co.uk)
In the front suspension the use of lightweight aluminium construction for components such as control arms, wheel carriers and axle subframes saves 5kgs over a conventional steel design. (motor-prime.com)
In addition to taking care of its suspension duties, the front axle subframe acts as a secondary load path and provides additional structural support in a crash. (motoring.com.au)