"You have a trig problem and a measurement problem.
The measurement problem is more difficult. "

I was wondering when someone was going to mention trig.

What he needs is something to act as a really huge caliper. Looking at the bottom of most cars there is no centerline to be found.

Actually is you can be absolutely sure the car is on a level surface, something like a plum bob could work. Measruing it accurately is still a problem, from the rim to a string ? And adjusting to minutes with only like 16" to work with ? No thanks.

But the good news is that you don't need the BMW alignment machine, they are not really brand specific. That means he does not have to go to the dealer and pay three times what an independent would charge.

On older cars I did set the toe in a few times. There was enough clearance to measure underneath wheel to wheel. Whaddya think the odds of that are here ? Did Slim leave town ? I never set caber or caster in the old backyard, but usually you don't heave to, even after replacing ball joints. They have to pretty far out of spec to affect it enough, really. Still, usually I would just pay the damn forty bucks and have it aligned. Of course that forty bucks is now a hundred, but how much is a set of tires ? A nice set of Dunlops or Michelins is worth the cost of an alignment, plus the car handles better. Plus with really good tires it rides better and quieter.

But some people are penny wise and pound foolish.