I just did the first oil change at 2500 Miles today and put in about 7 qts of organic 5w-30. My question for those of you who already have switched to synthetic is what brand and grade are you using and how often it is recommended to change. Did you experience any difference after switching to Synthetic. I saw a post on TT recommending to change the synthetic oil at 7500 interval. At what mileage did you switch to synthetic? Thanks.