I'm with Originhacker on this one, Ken42.
I never said 30wt oil would work on an Elantra or any other car. Re-read my post. Does Hyundai recommend synthetic or any special oil specs? I'm pretty sure the answer is no. They have engineers who probably know a lot more about lubrication than either of us.
VW, OTOH does specify particular oil standards, since they've had sludging issues with cheaper conventional oils in the past. GC seems like good oil, so it should work in an Elantra. However, it probably is overkill on lots of engines, perhaps even VW engines. Nevertheless, since VW goes out of its way to require VW 502 00, I'll go out of my way to find such oils.
What application did you want GC for? Are you looking for extended OCIs? You weren't clear, so the logical assumption is that you were talking regular use.