Interested in picking up a new BMW 4 Series with a turbo six? You've got options: you can get the 435i with 300 horsepower or spring for the M4 with 425 hp. But if it's the convertible model you want, we're afraid you'll be limited to the latter as the M division can't help you (at least not for the time being). But that's where Alpina comes in.
The aftermarket tuner closely associated with BMW offers the B4 Bi-Turbo (at least in Europe) with that same 3.0-liter twin-turbo inline-six massaged up to 410 horsepower that starts to pose a threat to the M4. What's more is that the Alpina's 442 pound-feet of torque eclipses the M4's 406 lb-ft, to say nothing of the 435i's 300.
Best of all, Alpina just confirmed via Facebook that it'll offer the B4 in convertible form, bringing the resulting BMW Alpina B4 Bi-Turbo Cabrio to the Geneva Motor Show. We'd expect the weight penalty to knock it slightly off the coupe's quoted 4.1-second 0-60 time, but not by much. If only BMW were to bring this one Stateside like it does with the B7 sedan.