I just bought this car 4 months ago. Currently it has 5w20 Valvoline full synthetic for oil and an off the shelf oil filter. My car has 83,000 miles plus on it! Please assist as I want the best for my Cobra! I live in Missouri where the weather gets hot and humid during the summer and I try not to drive her in the cold weather. Sometimes though it is unavoidable. What do you guys recommend for a great oil and oil filter???