Although a front plate mounted in the middle might not have
too much effect on cooling, I would prefer to leave that area open. The X needs all the cooling assistance it can get. So a side mount like
@jimmyx did (post #4) is a better option in my opinion.
Calif requires a front plate and it is a great excuse for a officer to pull someone over, then look for various other violations to cite. But I do not like the appearance of a front plate so I made a "quick release" attachment and kept the plate in the vehicle. If I got pulled over for it I would show the plate and say it just came loose, then reattach it in front of the officer - only receiving a warning. The good news is if you actually receive a citation it's what we refer to as a "fit it ticket", meaning you only need to mount the plate and get the citation signed off. Then nothing goes on your record.