335i saloon. Shape looks better IMO and when I owned one [briefly before realising I didn't need 2 x family cars, just one shed for the shops], I was nightly impressed. Understated but stealth, balanced yet a maniac and more power than you'll ever need for a 4 seater family wagon.
Couple of my 335 threads hereā¦
http://www.z4-forum.com/forum/viewtopic.php?f=5&t=49445&hilit=335i
http://www.z4-forum.com/forum/viewtopic.php?f=42&t=52230&p=760023&hilit=335i#p760023
Heard good things about E9x 330D's that are extremely mappable too.