When I asked him to look at it he asked me my oil and I was running 5w-30; of course he just said, put 5w-20 in it and check again so I did that back in Sept last year. It's been better since, but here we get into the issue of changing multiple things at once. I know for certain it never pings in the summer when its cold. But if you add heat (especially towing) and/or run 87 octane its terrible. It always sounds better in the winter months regardless of oil because my temps are usually colder.
Definitely getting a scope at some point. But considering I noticed it from the first month of ownership (brand new engine) and the owners manual mentions it specifically, I suspect it's "running as designed" and only a custom tune backing out some timing will get rid of it completely.
I have been running 91 for a long time now, but did run 89 for a few years before that. It really does not like 87 at all. One time I got caught in a small rural town with my trailer behind me, almost out of gas and filled up with 87 because of course they were out of premium, and I swear coming home on some hills out by Barrie/ON I thought I was going to spill all the marbles out on the freeway. Never, ever doing that again. I carry spare fuel jugs in my bed when making long trips now.