Dear fellow Z8 Enthusiasts,
I have recently looked at a Z8 Alpina with the issue of doming shocktower crowns. After reading a lot on this website and talking to Andrew MacPherson about the subject, I called BMW Classic in Munich.
The conversation with their Workshop Manager was quite enlightening and I would like to share their feedback with you since I have not read what they told me on this website.
The Workshop Manager said that they have an internal guideline on fixing the matter. If the doming is below 2 millimeter, they can easily and at a very low price "bend" the aluminum back into the original shape. It's a cold procedure without the application of heat and the shocktowers will not show any sign of the proecdure afterwards. The shocktowers can be considered to be in an as new condition after this procedure. No relevant structural weakness is left after this. Obviously the performance package should definitely be installed.
If the doming is above 2 millimeter, BMW Classic would not touch the shock tower crowns because the aluminum would be weakened further by bending it back into it's original position. In this case (if the owner want's it, the shock towers could be cut out and new shocktowers would have be welded into the car).
However, between the lines I also heard that the matter should not be taken to seriously. Even shocktowers that are bent more than 2 millimeters are not a problem if the performance package is installed. (At least as long as the frame is not bent and the hood still closes).
I have not bought the above mentioned Alpina for other reasons - so I will continue to look at Z8s. My take away regarding the frame matter: I would prefer to buy a car with completely flat shocktower crowns. If they are bend, I would be fine if it is below 2millimeter. If the doming is beyond 2 millimeters, I would probably not buy the car - just because it might be harder to sell the car to a well informed buyer.
All the best,
Daniel
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