Ok, everyone has an opinion, so here's mine.
The Alpina invoice includes the cost of the car, so, it appears Alpina purchased the car from BMW, and it arrived at Alpina with tinted windows, sunroof, silver (Polaris) metallic paint, black standard upholstery and, maybe, the 5 speed; the extra cost of these items is shown They also paid the transportation from BMW Munich to their factory. The rest of the invoice covers the additional work done by Alpina.