read my post in DIY on the subject.
http://www.987forum.com/forums/showthread.php?t=21515
I would recommend changing all of them before driving it. I'd think your idle would be the first thing to be wacky. You should be alright. again i would change the rest asap. The one closest to the passenger seat was the hardest. Follow my hints!! use a small and a regular size allen wrench. the large is good for breaking the bolt loose.