2004 2.5L with low KMs, its purty and an amazing drive. I'm not into racing so I would take the 2.5 over the 3 and save some money. I just love how it drives and when I do want to gun it is more then fast enough for me.
I am split between the z4 and 3 (both 2004s). It is just the z4 is cheaper (overall price and insurance), more fun the drive, and sexy as hell, but the 3 is also a smooth drive, pure luxury, and more practical.
Freakin hard to decide when this is going to be my daily driver for the next 3 years atleast if not more.