I cracked the OEM plastic cover last weekend when reinstalling it after changing the spark plugs. The two driver side screws are slightly off-center from the plastic, so the socket hit the edge.
I bought the Carbign Craft cover as a replacement, and these two screw holes are even farther off-center, by 3-4mm, so much that the screws can't be installed. Is it normal for this CF part to be this far off from lining up, and should I just slot the holes with a Dremel or drill press?

 

I would slightly drill the ones that didn't line up, starting with the bit that fits just right then work my way up a couple of sizes. I have an 8 and I bought an oem 9 spark plug cover and the holes on the new one don't line up exactly either.

 

my titek cf cover was off by mm's too. i just used a dremel to make the hole slightly larger.

 

Whenever I reinstall my spark plug cover (OEM VIII) what I found is that it will fight you a little bit no matter what. The trick is to thread all four first and then tighten them down. I cannot comment on the fitment of your new cover but I figured I would mention this because apparently it is a common issue.

 

I applied my Dremel to the two holes and made it fit. The screwheads are shifted over enough to prevent the use of a standard socket, so I used a screwdriver. A thin walled socket might work.