I would never run RFTs on my Z anymore, I never thought a small nail could do this to my Z !! Thank god I was doing only 90KMPH :cry:
http://www.z4-forum.com/forum/viewtopic.php?f=11&t=12430&p=188597#p188597
The falkens are better anyday, just get this and you should be fine, up and running...