Information is somewhat scattered and I'm still trying to get to understand it myself. There is a collection on strut mount data here:https://www.e46-forum.de/index.php?t...797#post901797
Sorry, I should have been more specific. What I meant is that early E46 models came with shorter strut mounts. Not Z4 mounts. According to the info I linked, strut mounts were 55mm tall until Nov. 2003 and 60mm tall after that. Here is the 55mm version from early cars and here is the 60mm version from later cars.
The early E36 and Z4 mounts (both have the same part number according to the link) were 45mm tall. This is the part that ZHPizza linked from FCPEuro. There seems to be a newer version of this part, basically having been replaced with Sachs 802066. This is the number I see cropping up when people ask about Z4 mounts, but this part does not seem to be available outside of Europe. The new Sachs part is 50mm tall (this is what must be for sale in the eBay listing I posted). In that case, the older Sachs part (45mm) that ZHPizza posted (link) would actually be 15mm shorter than a stock ZHP mount, or 0.6", which is quite a significant drop.
Then there is the XDrive version of the part that ZHPizza linked, which would be 31306785962 or this part: https://www.fcpeuro.com/products/bmw...ve-31306785962 If I understand correctly, it is the same part (and same height???) as 31336779613, except that it is sturdier.
Finally, there is Sachs 802186, which is 60mm tall like the stock E46 strut mount after Nov. 2003.
Hope that clears it up.