Buy Mobil One!
I have heard two questionable comments on Royal Purple (I cannot claim to their truths)
1. I spoke with A local performance shop and they spoke about losing a newly built engine using Royal Purple oil. (email me if you want the shop name)
2. A rotating equipment engineer at the refinery I work at told me that he has seen independent test results indicating that their products contained high levels of sulfur in them. He implied it was snake oil. Re recommended Mobil 1. My plant uses almost all Mobil products including synthetics.
There will be replies back to these statements claiming they have used it sucessfully and flags will fly.
Just use caution.
Mobil One is a pretty well accepted and proven product. Plus they sell Mobil 1 everywhere.