I truly enjoyed driving my 335 more in city day to day traffic than M3 but M3 is an amazing well balanced monster.....
And as far as Z4 being faster than M3...... pull next to a M3 at 60 mph and see what happens :-) Plus E92 looks much better than Z4!
Current: 2016 F10 535i xDrive AW w/ Black Dakota, ZMM, ZCW, ZDA, ZDB, ZPP, 688 & Black Grills.
Retired: 2011 E92 M3 -AW
....ED April 29th, 2010
Retired: 2007 E92 335i -Space Gray.....ED Oct 19th, 2006