You're right... The two drive very closely, the M3 is for sunny days, the Z gets to go out when it rains... 1500 over got it last week. There are no 2003 Cab's out yet, at least not in the Los Angeles area, I tried calling 5 local dealers. Plus the cabriolet M3's are just hard to get in general, and in that color. I didn't want a silver and no flat colors, the yellow is too loud, the blue looks like smurf blue, and the only two colors I like are the carbon black and the estoril blue (which is a special order).

 

I have both cars in my driveway!

Here is my assesment.

Z
better at acceleration, steering,gets more looks. Just feels more like a race car.

M
better comfort, & ride.

More like family sports car. You can throw your entire family luggage in the trunk.

My opnion, if it counts?