I've been hearing a lot about Royal Purple for older engines. What about my new(er) 07 ST V8 with 23k miles? Can I use it on that? I currently change my oil every 5k miles - with regular oil 10w30 as recommended - mostly because the truck's computer tells me to. If I were to use a synthetic oil and wanted to change my oil every 7500 - or 10k miles, how do I handle the computer telling me to change is at 5k miles? Is there a way to reset it? ... and ... can I change the oil with syn oil at these intervals?