You have the option of putting a larger head gasket in to drop the compression back to where it should be. I have a .4 mil shaved head and it raised the compression to 190 across all cylinders. Of course, the rings seem to be in great shape so I would guess .2mil over stock head gasket should get you to a better comp ratio.
Checking a head when you pull it off for warpage should let you know if any more material needs to be removed. If you are OK, then the thicker head gasket should get you back to normal compression. When you pull the head, check the gasket to see if its already a thicker one. If so, you may need to go thicker.
I also have chipped my ECU to almost eliminate the pinging. It pulls the low rpm timing down 5 degrees or so but retains the origional timing at higher rpm. seems to work pretty good so far. If you want the Bin, let me know. I will remove all the injector and MAF scaling to work with a stock engine.