You can't use a BOX WRENCH! You can't get it over the nut!
Note that the BMW tool is marked with the additive effect of the tool: 30 Nm at the torque wrench relates to 40 Nm at the nut. Those Krauts think of everything.
Ed in San Jose '97 540i 6 speed aspensilber over aubergine leather. Build date 3/97. Golden Gate Chapter BMW CCA Nr 62319.