IMO, it is easier, and cheaper to go with synthetics than the dino change ritual.
It is pretty well established that the syns provide superior engine protection, last longer, and tend to perform better in the complex engines such as the DOHC 3.5.
My routine is to change at 3,000 on the odometer and then change filters and add 1 quart at 8,000 with a full changeand filter at 13,000, repeat at similar intervals.
I believe this provides better protection and is much simpler and cheaper.
I am considering going to AMSOIL though, and plan to go with their air filter in my 2002 instead of the K&N.