How many miles do you have on your RA?
#48
It depends entirely on what type of driving you do and in what conditions as well as the oil you use. The only way to tell is to have a used oil analysis done and it will tell you if there is still life left in it.
#50
I don't think anyone can really tell you unless they have used Mobil 1 and had an analysis done. Being that we all have pretty similar cars it should be similar, but like I said, conditions, driving type (highway, city, mixed) and style (light/heavy foot, lots of boost,etc...) and maybe even climate would play a part. If I weren't doing changes at the manufacturers interval for warranty purposes, I'd probably run Amsoil and see how far I can go on it.
The bottom line is, get a used oil analysis done if you are really interested in extending your oil change intervals. That would be the safest way.
The bottom line is, get a used oil analysis done if you are really interested in extending your oil change intervals. That would be the safest way.