Is it worth using Royal Purple XPR Race 5w20 Motor Oil vs the regular synthetic 5w20? I mean will it give me anything worth the extra 10$/quart? I don't race (on race tracks) but quite aggressive and I like the sound on the highway in 4-5th gear, so I don't really use the 6th gear.
If I choose to go with AMSOIL, do they have a "matching" oil filter. I was going with the RP Extended Life Oil Filter for GT. Anyone has a suggestion for best oil filter? Goal is to keep the 5.0 as healthy and for as long as possible, it's most likely my last one and want to keep it top shape, one of my two boys will most likely wind up with it.
So I just noticed that on the oil lid it says 5w50. Just before I stored it away (6 months ago) I went to a Ford dealership and they used 5w20 (they gave me the left over quart of the synthetic mobil-1). I took it out about 2 weeks ago and drove it for about 150 miles. Should I go back to 5w-50?