Originally Posted by MysticBlue
That's not true. Left and right lights have essentially identical patterns... a horizontal line accross the field from left to right then towards the right side of the field the pattern goes up. The main horizontal line that both lights project should be equal. And they should both be aimed just below the eye level of oncoming drivers on a level straight road. If the right light is higher than that, it will blind oncoming traffic just as much as the left light would. And if the left light is lower than that, it won't make any difference to oncoming traffic and will just give you less light. So there is no point in aiming the left light lower than the right. They should be even.
Not true. That's one of the reasons the part numbers for lights aren't the same for LHD and RHD cars, and no the passenger side light does not affect the driver as much because of how they're aimed on a horizontal plane. I can't find BMW's own diagram at the moment but there's another thread about this here: http://www.e90post.com/forums/showthread.php?t=154940
But regardless OP if you're going to adjust your headlights, just turn each knob the same amount and you'll be fine.