driving a 3.1 v6 in a 98 pontiac grand am, just finished the arx cleaning phase with Havoline 5w30 oil. considering switching to synthetic at this point, looking at Mobil 1 5w30, Pennzoil Platinum 5w30, or gc 0w30 for 7500 oci. been using wix filters, car has around 95k miles and is mostly highway driving. any recommendations on these oils? thanks