Hello all, have been lurking for some time. Just bought my Fathers 2008 Acura TL from him last week with 112 thousand miles on it. He would get the oil/filter changed when the MM would hit 20% at the local garage with 5W20 conventional oil & there budget filter. The car only seen conventional oil its whole life since he bought it new in 08. Would it be ok to use a synthetic oil at this point of its life? I was leaning on using a high mileage oil. What should I use, a conventional high mileage oil or a synthetic high mileage oil? Does not leak or burn any oil since day one. He bought a new 2018 Toyota Avalon. Gave me a good deal & I bit. Been reading that Fram Ultra filters are good also?