I ordered new plugs from german auto parts for the benz and they came in as WDC8 (I think that was the right lettering) but what I pulled out was WDC9. Once upon a time I knew the answer to this but is that a different temperature plug or just a different factory pre gap? the plugs came out clean but some of them had a gap of almost 1.2mm! pretty serious gap to the .77 or so that the Haynes manual shows.

Thanks for any help