I bought the '97 Z3 2.8L with the M body style, wide tail and tires, the first year of this style. I think this body is a classic. The Z4 is a bit crisp for me. I have owned my car for 10 years and have had no problems other than a minor driver's seat rail play (seat slid back/forth) which I got fixed under warranty. In 2000, I compared this vs. my neighbor's Porsche 2.5L boxster he wanted to sell me and this vintage of the two cars didn't render a big difference. I felt the BMW 2.8 had more power than the Boxster and handled as well when I pushed both on a very windy back road. There is a huge difference between the 4 cyl and 6 cyl BMW. Once I drove the 2.8L, I said no to the 4 cyl.
Straight 6cyl power, handling, interior style with red extended leather on the doors and dash, wood steering wheel/shifter/console, exterior styling with curves and wide tail. The lines on this body are a classic. Harmon-Kardon premium audio is excellent and a must. Also 17" 5 spoke wheels.
Rear part of center console (storage and cup holders) are cheap looking and feel. Need better design on lids, hinges, and materials. Glass rear window rather than plastic. Next model year had lined roof which is quieter.