This rims are certainly not original, as you stated in your first post, mentioning they are genuine.
Secondly, original 18" rims have ET50.
And then concerning spacers. Something I personally would never do. Most will not have problems, but the wider the spacers, the more the bearings suffer. Just a few mm won't do much harm, but you can sometimes see spacers of a few cm.
And on a personal note, if I would be in the market of buying any vehicle, and I see non original rims and/or spacers, it would be a big no for me.
But, everyone can make out for themselves what they want to do with the vehicle.