[Tspringer]

Screw it up? How do you screw it up?

A first timer may have to adjust and tighten each adjuster screw a couple of times to figure out how to tighten it without it moving and changing the gap, but its pretty clear when its right and when its not. I really do not see this being a "danger" thing at all.

The comments are correct: ITs EASY. Given, my little '69 its very easy to get around in the engine bay and on later models access may make it more of a knuckle buster but the basic game is the same.

It is one of the more simple mechanical jobs on a 911. It is just like a VW bug. Get the right tools (available right here), make sure you take the advice and order some extra feeler guage blades and go to it.