I'll chime in again.
My V7 was pinging due to a tune in Japan. I noticed it on the 3rd pull driving around in 2nd gear. The car drops boost to 0.5 BAR and retards timing to save itself when the knock sensor picks up pinging. Other then that, it drove around perfectly fine (I was also on 94).
It's hard to hear, but if you pull the car with the windows open, does it sound like you are dropping marbles into the cylinder or the road?
Stock boost map is max 17 PSI. They will boost to 18-19 PSI with the waste-gate pegged shut and boost creep. Does it still have the stock boost solenoid?
I'm almost willing to bet this is due to overboosting that's causing the car to ping. As other's have said, changing the MAF and fuel pump is great as the stock ones seems to fail overtime. But first you need to figure out why your car is boosting to 1.5 bar.