My knock problem theory. Make sense or not?

[Onefast99gsx]

Well tonight i changed the fuel filter(What a f'n pain in the ass). I did on my old car and I WAS NOT looking forward to it. I put the BPR6ES plugs back in and also lowered the boost. I'm at 19psi. It felt ok for 19, of course it felt slower than 24 but i'm doing the back to the books tuning here. Log would look something like this.

Upto 5700 in 3rd gear: No knock whatsoever.

RPM Knock
5769 .4* thru
6219 .4*
6229 0
6345 0
6378 .4 thru
6567 .4
6591 0 thru
7036 0

At this point, i can either lean or richen it, OR lower the boost a pound or so and see what it does for me.