vtraudt

I am dialing in the fuel pressure for my Giac PC-16 tune.
Giac calls for a 3.0 bar (43.5 psi) while some forum users suggest 2.7-2.8 bar (39.0 to 40.6 psi).

Irrespective of the value: is the fuel pressure measured

a) at idle
b) with vacuum line disconnected from fuel pressure regulator
c) with vac line connected

My (non Audi) tuning buddies set their pressure with the vac line disconnected. What pressure is Giac referring to?

Same question asked differently: is my stock 4 bar fuel pressure regulator showing 4 bar at the gauge with the vac line or off?