Alignment gurus

[grannyknot]

Two questions,
I have a print out of the alignment done on my Z4 just before I bought it, the shop used the specifications for a Z4 with 18" wheels but I know the car was wearing 19" wheels when the alignment was done.
Would that extra inch skew or exaggerate the results of the test?

I've been looking around for a pair of rear adjustable lower control arms and on most of them they state their control arms are good for adjustments from +3.0 to -1.0 camber.
Those are the exact opposite of the numbers I'm looking for, in what situation would someone want +3.0 camber?

I'm looking for at least -2.0 of camber.
I've always thought negative camber means the top of the tire is leaning in toward the car and positive camber means the top of the tire is leaning away from the car, have I been wrong all these years?

[maupineda]

No impact to alignment by wheel diameter, as it is not used to setup the geometry, also, if used the correct 19in sizes, the overall wheel diameter should be the same 660mm, or 26in.

225/45/18 = 225/40/19
255/40/18 = 255/35/19

I don't think you need more than -2.0 at the rear, and the stock system should be good to that, as is within the BMW spec. I have rear R&E arms and have -2.0, so not sure they give me much other than a spherical ball joint. OE Rear spec is -1.8 +/- 0.25

I aligned the car to E46 M3 CSL specs, and yes, the car is sharper and responsive, but the front follows cambers much more, I would shoot for a bit of toe in to have some neutrality on the road. I would start with the rear CSL alignment and OE for the front.