Although I've never been a big fan of Beemers styled by the eternally controversial Chris Bangle, there's something about the 06 Z4 M coupe that really appeals to me. Maybe it's the last of the big S54 cast iron sixes, or the fact that it's renowned as a bit of a brute to drive hard which gives it a raw muscle car-style edge. Fact is, whether you love or loathe the styling, it's always going to be controversial - which is a very desirable attribute in any collectable car I reckon. Plus BMW made less than 5000 of them and only about 1000 of those were in RHD, so it also has rarity on its side. I reckon it ticks a lot of boxes as a modern classic and collectable.