I would like to add my experience to the Idle tips and with thanks to those who on the forum helped me.
My 99 C5, 6 speed with cam change, LT headers had a lumpy 700 to 750 RPM idle. I set the Idle at 910 RPM and was happy until I pushed the clutch in to roll up to a stop. The engine went back to the old rolling Idle.
In Tune, Engine calibrations, Idle,double click on "Desired Idle Speed", there are four columns under Conditions, labeled:
In-Gear A/C on, In-Gear A/C Off. In P/N A/C On, In P/N A/C Off.
I had set the idle speed in the two on the left, set the idle speed in all four columns for the engine operating temperature range. I started at 1000 RPM for a cold engine and went to my desired 910 RPM for normal operating temperatures for my 160* TStat. I would set the normal speed 10-20 RPM high in the two right columns for the manual transmission. This worked for me.
Cheers, Curt