So I went ahead and ordered this board (
https://www.asus.com/Motherboards/H170M-PLUS/overview/ ) as I picked a non "K" version of the i7 so I am not interested in overclocking.
Parts were delivered today. As soon as I looked at the board (without even taking it out of the anti-static bag) I noticed the "PCIe 3.0/2.0 x16 (x16 mode)" was too close to the cpu socket. I know I ordered this cooler (
http://noctua.at/en/nh-u12s.html). While it's not the 14 or 15cm fan version. It's still bigger than a normal stock and/or 9cm cpu cooler.
So I went online here (
http://noctua.at/en/mainboard/Asus_H170M-Plus) and noticed the cooler I had ordered was not listed as compatible with the board.
I contacted PCandParts and asked if I can replace the board with an "Asus Z170K" and they said I have 5 days (from invoice date) to return a product but... I would have to pay 2 x delivery (once so that Aramex picks up the part I want to return and another time so that Aramex delivers the new product). They cannot do that on the same day as they have to check the condition of the part I am sending back.
Moreover, they stated that restocking fees might apply. They said "we might reduce or cancel restocking fees for old customers if the item was not used at all and is still in the same condition it was delivered in".
I hope I won't end up paying more than 8$ for the double delivery.
I am not blaming PCandParts. The mistake is mine and I should have guessed that a MicroATX board will hardly fit a big cooler and paid the extra 20$ to get an ATX board even if I didn't need a Z170 chipset.
Conclusion: lesson learned. Don't make the same mistake.