I'm on my iPhone so can't see the full description but they should be et43 front and et21.5 rear so yes they are the Z3m fitment but you will need 7mm front and 10mm rear spacers from Schnitzer and longer bolts.
Have a look a my journal as I've just bought a set and it may have been from the same seller I think. If so they are brand new and he had a few sets to sell presumably of old stock. I bought mine when he had make me an offer and got them for less than 900 euro from memory. He's been selling them for a while so make him an offer but even at that price they are less than 50% of the new price from Schnitzer (though they would include the spacers and bolts)
They are great looking wheels and BMW fitted them as standard to a special edition model they sold in the south African market.
The online translation is not converting it all properly but it says that even though they were all ordered together, one of the wheels is shinier than the others but you can only tell when you put them all together. It's a private sale without warranty and he's inviting anyone to go see for themselves.
I've tried a few translation sites and they're all struggling a bit with the text but this is the gist of it.
The second link are perfect as I described above and are from the guy I got mine from as I recognise the picture in the advert. Bear in mind I paid half that price for them but if this is his last set they are a lot cheaper than list price.
I found a Schnitzer Mini One.... really nice but it's lhd.... but it's really nice
and I found 1 roll hoop for 75 euro - where on earth is the other one.... no 18" wheels for you though sorry.... quite a few 17's though.
Problem is with genuine ACS alloys is unless your lucky they just don't come cheap. I waited a few years to get my hands on a set of Type 3 Racing for a reasonable outlay and gave up in the end. You get the odd set of Type 3 one piece at a reasonable price when refurbed but still looking at over 1K. I gave up and bit the bullet and ordered a new set. Of course you get the tatty sets which can be a good buy if you want to take the refurbed route.
If the alloys are only a little over your budget go for it as you don't know when the next set will come along.