As an sd owner i know the brakles are uprated for the sd. But as for the ZF gearbox, i am not sure but if you look at the spec sheet they have the same ratios so i would think they would be the same torque rating. I cannot see even BMW having 2 gearboxes with the same ratios but differing torque rating. So the 280 BHP that most reputable tuners take the d up to would be safe.