Crew,
You're not the first to notice an increase in valvetrain related noise with Mobil 1. Some on here will debate its existence, demanding absolute proof in the form of some study or what ever. I say hogwash to that because I know what my ears have heard. I personally have observed it not just once, but in two successive OCI's in my Maxima. I have also read numerous posts (especially from other Nissan VQ owners) who ask the same question about the noise issue with Mobil 1. In my case it was the older 10.? cst 5w30 SuperSyn (released after the "Tri-Syn" formula). I've always leaned more towards the thin viscosity causing it, as the noise immediately diminished when using the slightly heavier Castrol GTX 5w30 and then especially with GC. But lately, I've been reading on some friction modifiers and other additives affecting valvetrain components (in a positive way), so even basic additive differences can justify the noise issue. I don't know with 100% certainty what causes the noise, but I am 100% certain the noise was there with Mobil 1. Now that Mobil 1's 5w30 is thicker, the noise issue may have been solved; I don't know. But I'm very happy with the quietness and smoothness from GC and therefore won't switch back to Mobil 1 anytime soon.
I'm not slamming Mobil 1, as I think it can be a good oil in the right engine. I however don't think it is the right oil for Nissan VQ's, and quite possibly for some other engines as well.
If you're happy with the GC performance, I'd use it for several OCI's and get some UOA's (as long as it is the proper viscosity for your Audi). Then you could try several with the Amsoil (another good oil) and compare UOA's along with subjective impressions like engine noise, "pep", etc... I think several successive OCI's with the same oil are needed for better accuracy in UOA's. Switching from one chemistry to another all the time just doesn't lend itself to accurate comparisons because of leftover oil/additives, etc...
Based on your UOA, I don't think you have any problems with the GC. The iron looks suspiciously like leftover from breakin. I say this because your other wear metals appear disproportionately low for there to be a mechanical problem. And I'd think that if the fuel dilution was a real problem, your lead would've been higher.
Dave