I love the 107s too, but given the fitting limitations I can see why they probably haven't been fitted to E89s.
I did the opposite and fitted E89 wheels to an E86, which worked pretty well as they sat further out in the arches without spacers!
I bought a set of 295s (staggered 18s) for my 2nd E86 and really liked them, although they seem to be NLA so used set would be the only option.
As we're on z4forum a photo seems essential. :lol: