Both cars gain a boost in power, aerodynamic improvements, a revised exterior design and new technical software.
The updated Alpina B3 is powered by a 3.0-litre in-line six-cylinder engine with an output of 488bhp - an improvement of 32bhp over the previous car.
Torque is also uprated by 22lb ft to 538lb ft. The reserves are channelled through an eight-speed automatic transmission.
The B3 Saloon covers 0-62mph in 3.6sec and estate-bodied Alpina B3 Touring completes the sprint in 3.7secs. Top speed stands at 190mph.
Alpina’s D3 S, meanwhile, uses a 3.0-litre straight-six diesel engine with mild-hybrid technology supported by a 48V starter-generator, which, the firm says, improves throttle response and efficiency.
It has 5bhp more than the previous version, at 355bhp, and generates 539lb ft of torque. The D3 S Saloon takes 4.6sec to dispatch 0-62mph and the Alpina D3 S Touring 4.8sec.
The D3 S can reach a top speed of 168mph. It's also capable of 40.9mpg.
Both cars receive various exterior design changes, including additional components at the front and the rear to improve aerodynamics.
Inside, each model is equipped with a 14.9in curved display, along with a digital driver's display and BMW’s eighth-generation iDrive system.
Both cars are open for order now, with prices starting from €88,600 (£74,550) for the Alpine B3 and €77,050 (£64,831) for the D3. The first deliveries are expected in October.