Canvassing opinions...

[mr wilks]

Well that's what I was told, but just had a look online and they can be had in 18"! Unfortunately they don't seem to fit the z4?? That's what LK Performance is saying anyway...

Quite possibly , , maybe search for them in 3 series E90 fitment as these would suit Z fitment even better

 

[ronk]

Has there been any horror stories of aftermarket wheels cracking like the "top price - top quality " BMW supplied kit ?

I don't consider the majority of aftermarket wheels to be any inferior or superior to OEM however at the lower end of the scale there are many cheapo "reps" that are pretty poor quality avoid those no name alloys & you should be fine .
If you consider the number sold & in use on this forum alone i can't ever recall any horror stories from using non OEM alloys

That was the point - we've seen loads of posts re 326 an 29# whatever cracking - but nobody seems to mention any problems with the aftermarket wheels - perhaps they are doing something right?