Hi Monzon, I made the move from Z4MC to M6.
It could be that the salesman is now leading you down the M3 route as BMW have ceased production on the M6 (FOOLS!!)
I tried M3 coupe, M6 coupe and M6 cabrio and the cabrio won my heart, it`s just such an "occasion" car. I loved my Z4MC and would have kept it as a weekend toy but getting married in 12 months so funds are tight.
As a drive the M6 is utterly different from the Zed, you can relax, and let the car drive you. Try that in a zed and you`ll be either kissing armco or tree bark! The chassis and suspension are very very well resolved with three stage EDC which works well.
The noise, although a bit subdued, is one of the greatest automotive road car noises this side of an exotic and is one of the reasons I went with the cabrio.
Don`t be expected to be wowed by lightening getaways like you can in an Z4MC/R the power and pace of the V10 doesn`t really come into its own until north of 80leptons. That`s not to say that it`s slow because you can still get a 4.4secs to 60 time fairly easily but it`s the power in 2-3-4-5-6 from 6000rpm to 8250 red line that is simply astounding. One you are rolling the weight doesn`t play such a part and the M6 will beat some very serious machinery. There is a lot of vids on you tube that are testament to this.
Be aware that it is a VERY expensive car to run but very enjoyable. Mine is in M mode P500 traction off as soon as the ignition is on. It`s pointless driving it in P400, negligent fuel savings and you may as well have bought a 645/650!
Fit and finish is very good, no rattles and really does have that hewn from granite feel that is perhaps a little absent on the Zed what`s with it being built across the pond.
I shall be keeping mine at least another 2 years then either supercharging it (once it is out of warranty) or going ferrari 612 Scaglietti. I doubt the big Fiat will be as fast as even the standard M6 though?
If you need any more info please drop me a line.
Jon