Don't worry to much about it. I did the same thing and use a zip tie to keep the coil from moving around.

 

I snapped mine off with 400 miles on the truck. I never did fix it. I wouldn't worry about it. Think of it this way, you don't have a scew holding plug wires on any other type of car. It was never an issue, it fits secure enough to pull 1.5 60's and low 11 second 1/4 miles.

 

Wow this thread hits close to home!

I snaped off the #8 coil pack bolt on mine 2 weeks ago.
Since then Ive been driving it without that bolt and it hasnt missed a beat yet.

It makes me feel a lot better knowing that some of you have missing bolts and it hasnt caused any problems.

Andy