Use the synthetic as soon as possible. I like Mobil1 Delvac for my F550. You might also want to start oil analysis with a service like Blackstone Labs, etc. Also, Amsoil and Redline oils have excellent reputations, and Amsoil does carry extensive sideline products such as filters, bypass systems. The synthetic with the oil analysis will keep the PSD going several hundred thousand miles before teardown/rebuild. The oil analysis will save you money in the long run because you will be able to extend the change interval.

Good luck !