BUCHLOE, Germany — Alpina, a specialist in tuner BMWs, is making a return to racing after a 20-year absence with a car based on the BMW 6 Series. The public will be able to see that car, the B6 GT3, at the Geneva Auto Show next month.The Alpina factory team will enter the FIA GT3 racing series with its B6 GT3, derived from the BMW 6 Series. The B6 GT3 is also inspired by Alpina's B6 S road car
