Both cars handle well; predictable and accurate when using premium tyres.
Power is usable but not necessary on UK roads..Definitely feel the extra oomph in 2nd gear...anything higher than 2nd and your into silly speeds.(referring to entering and exiting corners etc)
I love my m3 and it's incredibly practical but I definitely see myself owning a z4 coupe again.
A benefit of the m3 e46 is its cheap road tax compared to the z4m
I'd like a z4m but I can't justify that road tax