It's a fine car, the Alpina. It's easy to position on the road, the absence of run-flats improves the ride beyond measure, and the engine - the twin-turbodiesel - is an absolute peach.
All this leaves me thinking that this is the car that shouldn't have been built... shouldn't have needed to be built, rather.
BMW has an excellent record tweaking chassis set-ups, the (admittedly expensive) Michelin tyres are available on the open market, and BMW already has the engine. So... why don't they make the car?