My coil cover warped slightly at one time, causing some of the bolts to not engage properly. I lived with that for awhile until I did some tinkering with plugs and coils later on. Forcing it only served to crack the cover in half!
Car runs fine regardless, but BEWARE of introducing lots of water to the motor exterior if your cover doesn't have a good seal (for those of you who do wash their engines)...
...has anyone ever found a source that supplies replacement covers?