I've gotten caught up in the craze over the GC like the rest of you. (I once had a stash of over 80 gallons of Delvac 1 that I bought at a very good price, so I know a bit about "oil collecting"). I have a car which needs an oil meeting MB 229.5; the only two I have found are the M1 0w-40 and the Elf Excellium 229.5 (but Elf apparently lost the only 2 cases which were in the US; at least according to their NJ offices!) Apparently the GC meets 229.3 rather than 229.5. It is possible that 229.5 didn't exist at the time GC was manufactured and was wondering if anyone knows the difference between the specs. I was considering the GC for an 05 Mercedes CDI.