Originally Posted by Amalgamated Tom

The manual doesn't call for new studs, but says to use new nuts. The studs can be real pain to remove. Not sure there is a good home mechanic way of telling if they've been over-stretched unless something is obvious (one of them looks damaged or stands taller, etc). You can't measure their length without removing them and once you've removed them you might as well put in new ones. I'd say to change them if you are chasing recurring head gasket failures (or planning for tons of boost/hp), but not if you are just changing a gasket after a long happy life. Pretty sure the torque specs are in clarks-garage and in my write-up in the link below.