Also, you don't have knock sensors, so I bet your running a bit lean maybe?
I throw an 02/Knock Control code at extended idle periods because it runs a little rich.
I never hear pinging in my car and I just installed it 3 weeks ago as well.
Also, you really need to work that intake out better and need to get a filter on that AFM stat.
I have a pretty good suggestion to clean up the install a little bit, since I just went through this as well kind of:
1) Flip your Intake bellow around, and route the ICV and its connected hoses on top of the S/C. This is how Downing specifies to do it in the manual
2) Doing this will allow your AFM to sit better and not on top of the radiator.
3) Re-work the Crank case vent, PCV, and ICV locations. Refer to my pic below.
4) What is that spring-clip plug sitting on top of the intake bellow?
NOTE: AFM plug was NOT cut and spliced in these photos yet.

