So I've been useing edge 10w30 and its great! My OCI is always 7500 for warrantee reasons. I was thinking of trying the GC just to see if there is a difference. It should be fine as the car says 5w20, 5w30, or 10w30 when above 0F. GF-3 or 4 and SL,SM or above. So Im good there but what do you guys think? Oh BTW I live in Atlanta GA now and the car is driven in hwy traffic about 500 miles a week. The Sonata is the 4 cylender.