id love some proper alpina wheels too, but id just damage them and the moneys better spend elsewhere for me. saw them in person recently and i think they are the best wheel for the z4 looks wise.
I can vouch for Alpina's being a pain in the arse to clean! They take about the same time as it does to wash the rest of the car! Well worth it tho.
The chrome versions are usually always replicas.
Not sure if the first image is a photoshop, as the wheels dont quite look right on the car, likewise, they are not the same Alpina Dynamic's which were made for z4, so could only assume they would be off a z8 or something. Doesnt look quite right tho.
Pic of mine below.
The alpina's are my pride and joy. Managed to get a genuine set off a Roadster-S.... cost me an arm and a leg, but worth every penny, and look truely awesome on the car, the pictures just dont do them justice!
I can respect everybody's taste, but on a silver car...chrome wheels are a must IMO. The hyper silver just looks do damn plain. Would of gone for the original finish on most other colors though.