I had the same issue w/ my Boxster as have many others. Easy fix? You could possibly fill the holes w/ JBWeld then re-tap. I didn't try this b/c I wanted a more complete solution.
So... here's the write up I did by replacing the cheap worthless factory retainers w/ steel nutserts. Didn't take too long but best of all, it was done the right and the way it should have been from factory...
Good luck
