Just in case anyone was thinking of going the 718 route after the Z4M since it's been mentioned somewhere in here
Had one this weekend on a bit of an extended test drive.
First impression, build quality is top shelf. Lots of leather, and metal trimmings, all the buttons have a solid feel, everything has a nice assuring clunk, no rattles. Visually it is stunning from the outside. Strangely feels like you sit quite high on the inside, and you can only drop the wheel o far (electronically)
4 pot takes some getting used to but it has a very nice tone and the aural pleasure from the roar when you really make it angry is definitely something. The PDK is spectacular as much as I prefer a manual. It does exactly what you want it to do, when you want it to do it. Gear shifts are lightning fast. The thing is as sure footed as they come - it handles tightly and forgivingly but when you wind it up and get into it above 4k you make a lot of progress.
There really aren't any downsides to write home about, except for one depending on your outlook - the 4 pot.. It does a mega job for the engine size and form that it is, but it's the only reason I couldn't fall in love with it