Alpina has launched hardcore GT versions of the B3, B3 Touring and B4 Gran Coupé before BMW takes full ownership of the Buchloe firm next year.
Touting higher performance, aero-optimised design tweaks and chassis changes, the new GT models are due on sale in Germany from November, with a UK launch expected to follow in early 2025.
The new GTs use the same twin-turbocharged 3.0-litre straight-six petrol engine as the standard B3 and B4 but with a 33bhp power boost to a 522bhp peak, which is delivered higher in the rev range - between 6250rpm and 6500rpm.
Torque remains the same, at 538lb ft, sent through all four wheels through a ZF eight-speed automatic gearbox.
Each car's 0-62mph time has been cut by 0.2sec in line with the power increase, with the fastest - the B3 GT saloon - dispatching 0-62mph in 3.4sec. It has a top speed of 191mph – 2mph faster than before.
The GTs have also received chassis tweaks to improve handling and reduce roll, including a stiffer damper mounts, a reinforced bulkhead for more precise steering and a thicker rear anti-roll bar.
Spring rates have also been recalibrated for better ride comfort.
The B4 GT coupé specifically receives additional reinforcement for the anti-roll bars, as well as recalibration for the steering, dampers, four-wheel drive system and limited-slip differential.
Design changes are in the same vein as the larger B5 GT. The B3 and B4 GTs wear canards on the front bumper, a redesigned rear diffuser and black exhausts.
They're further marked out by bronze 20in alloy wheels and bespoke badging.
The GTs' interiors are decorated with bronze stitching and paddle shifters, as well as a plaque on the centre console depicting the model number.
German prices are €101,700 (£85,600) for the B3 GT saloon, €102,900 (£87,570) for the B3 GT Touring estate and €105,100 (£89,400) for the B4 GT Gran Coupé.