Alright guys, got tuned a few weeks ago. Here is my mod list:

2.7 pulley
60# injectors
k&n intake
ls4 throttle body
mid length head/catted down pipe
2.5 catback
cooling mods

Ive been researching this for 2 weeks now. The idle jumps from about 850-1200, I assume that's just how the ls4 is from what I have read. I thought I had a leak somewhere, so replaced the throttle body gasket, supercharger gasket, and IM gaskets (I have the phenolic spacer).
All vacuum lines are good.
I can deal with the idle if I can figure out why I cant build boost. It jumps from around -15 to -20 at idle, and haven't seen more that 8 pounds at WOT.

Here is a video at idle.
Thinking maybe the boost solenoid is bad? I plan on checking when its not raining.
Besides that, im at a loss.

 

Boost solenoid was bad, replaced it, still no boost.
UGH
It seems when I go to do a pull, boost drops to 0 and builds back up to -17 to -19.

I don't know what else to do.