Well, my first post must have gotten lost. Here go's again: My Hustler super Z with 25 KAW has just 6 hours on it. The dealer said change the oil at about this time. Should I change the oil filter also? What kind of oil? The manual says 30 or 40 weight in my heat conditions. I was thinking synthetic valvoline 20W50, especially since I live in Florida. Any help!