The 2017 Alpina B3 and B4 offered an optional mechanical LSD for 7 years.

Alpina Automobiles Australia is offering buyers of its recently introduced performance-enhancing BMW range the option to upgrade their final drive with a mechanical limited slip differential (LSD).

The new differential has been designed specifically for the Alpina B3, B4 and B7 models by high performance transmission specialist Drexler Motorsport and is offered for $5130 including GST and installation at a BMW Authorized Service Center.

Alpina says customers who upgrade can look forward to improved traction when driving enthusiastically and minimizing tire slip, as well as easier driving when the limit is hit and "superior directional stability."

Like any product from the German precision engineering company, the Drexler LSD is handcrafted to motorsport standards using forged gears and a CNC machined housing.

Unlike later electronically controlled differentials and torque vectoring control systems, the mechanical LSD uses a multi-clutch package to sense torque and direct power to the wheel with the most grip.

The more traditional approach is often preferred by purists and driving enthusiasts for its easier operation and unique handling characteristics.

Existing switchable driving modes and other adjustable systems such as suspension and engine operation remain unchanged, while the Drexler differential operates independently and without electronic control.

Alpina cars were presented in Australia last November.

In Europe, Alpina says roughly 20 percent of its customers choose their vehicles with LSD upgrades, but in the high-performance Australian automotive landscape, local equipment predicts demand will be higher.

The device can be specified when ordering an Alpina vehicle or retrofitted in the case of customers who have already received their vehicle.

Alpina vehicles were introduced in Australia last November and are distributed by In Motion Group through the BMW dealer network in Doncaster, Victoria.

The range includes the BMW 3 Series-based B3 sedan and Touring, the 4 Series-based B4 coupe, and the upcoming flagship B7, which starts life as the 7 Series.

Drexler has been supplying high quality transmission components to the automotive industry for 30 years and specializes in limited slip differentials with previous involvement in both motorsport and road vehicle projects.