Dave, there are a few apps that let you lock white balance from a certain area of the frame, then lock exposure elsewhere, then frame and shoot. you can lock the WB on the white of the car and be sure it's correct first.
2009 135i | space grey | sport | navi | hifi | heated
dinan stage 2 software | bmw performance exhaust
kw v2 | hotchkis front sway | vmr v710