[Gunter]

Rodney:
Pinging can be from a lean mixture, or advance timing, or both.
I would have the distributor checked/recurved?
The internal springs together with the vacuum give you the right timing at various RPM's.
DJC911: With high idle when warm I would concentrate on the Auxillary Air Regulator (AAR) and AAV. Sounds like the "halve-moon" opening in the AAR is not closing. Before changing the WUR, system pressure, and control pressure should have been checked. WUR's are expensive and sometimes can be fixed; ask for the old WUR back, especially since you still have problems. Avoid places that don't do system-checks to determine the problem; anybody can change parts until the problem disappears.
diabolo88: It's my understanding that turbos need to be set rich to avoid detonation. Soft brake pedal usually means that the brakes need to be checked. Bleeding for sure and, when were the calipers rebuild? Master cylinder? How are the rotors, and pads? To check if your Servo works, with engine off, press on the brake pedal, start engine, your foot should feel the pedal going down.
djdsc: Depending on the year, timing adjustments vary.
'78-'79 has 5deg @ 950 RPM, vac. connected (26deg @ 6000 RPM).
'80-'83 also has 5deg @ 950 RPM vac. disconnected (21deg @ 6000 RPM) (The don't differentiate Adv./Retard and don't say to plug the lines)
Obviously, when you pull the retard line off the distributor, you'll have a small vacuum leak.
In my earlier reply, I described the way that I set my timing; It works for me. If anyone wants to do it differently, go for it. As long as it works.
I can only repeat: Get a Bentley Repair Manual to learn more about your 911 and experiment.