OP, why not change to Amsoil, and go to a 10,000+ mile oil change. I have been using Amsoil 5w-30XLI in my 18′ 3.6R since I had it’s first oil change at 5611 miles on September 22, 2018.
I also have Fumoto drain valves in my cars. They are great, put a hose on the nipple in a container and open the valve, no mess.
In 2013, after changing the Amsoil in my 05 Legacy GT turbocharged wagon, I sent an oil sample to Blackstone Labs, with 7000 miles on that oil, 5w-40 Amsoil. I was told to leave the oil in there for another 2000 miles and send another sample. For over 160,000 miles on that engine, I did 7-8000 mile oil changes, the engine was running 21psi boost all that time, stock is 13psi boost.
