I thought I had a picture? The turbo piston ring land areas are different from N/A dished pistons. I believe the distance from the top of the piston to the 1st ring is longer on the turbo piston, and each space between each ring is larger than N/A dished pistons.
I found what Gollum says to be true. The N/A has too much of a CR. I ran 20 lbs, with timing at about 12deg?? pig rich, and still had detonation. On my true turbo motor now, I can run 16lbs, at 11.5 afr, and 20deg timing. After that the meth starts spaying.