Since we're talking low-SAPS oils in gasoline cars here I thought I'd post a link to Artem's UOAs with Amsoil Euro 5w30. It's not a turbo Subaru, but it's a modded Civic Si, driven hard. It held up well, including the TBN, wear metals were also excellent.
All in all, I'd say the jury is still out on low-SAPS oils in gassers in the US. Gathermethewool is modded and shows a lot of fuel, 1wrxtra's latest doesn't look like Amsoil Euro, and his previous UOA looks pretty good. Now if only we could find some M1 ESP and Pennzoil Ultra Euro UOAs in gassers...
Oh, and Dennis- take a look at the Lubrizol chart of 504/507, it pegs the meter for wear, sludge, piston deposits, and oxidation. The performance specs of 504/507 (Low-SAPS) certainly don't scream "girly-man oil" to me... There's always risk in change of course, but in a few years with the low-speed detonation requirements of GF-6, lots more oils might be "low-SAPS".