We've had a few discussions here on oils. If you go to the Facebook side of things, you'll have hundreds of people using AMSOIL.
I personally use AMSOIL Signature Series. I'm tuned by BNR, and I town my boat with my Cruze (~900 pounds), which means extended levels of high boost. I'm no longer light with the throttle on acceleration either. Even with a boat, I'm ahead of traffic after a red light.
That said, I run 15,000 mile drain intervals, changing my Wix filter at 7,500 miles. Over a dozen oil analysis reports from members both tuned and stock have shown this to be a solid, safe change interval on this oil. Because the oil provides much better protection against deposit formation being a Group 5 oil, even at 15,000 miles, it is a better product to prevent against turbo seal and piston ring deposits through an exceptional oxidation stability. The extended drain intervals save you time, and negate the additional cost over lesser "synthetic" labeled products.
Currently, I have 9,500 miles on my change of oil. I've towed my boat to the lake half an hour away and back at least a dozen times, and have seen no oil consumption. My oil level has not dropped from the "full" mark since I put it in there over a year ago.
As Tomko noted, there's little question that this is the best oil you can get your hands on. Send me a PM and I can get you a quote on some delivered to your house; the cost is really quite reasonable. If you're looking for something local though, grab some Pennzoil Platinum; its one of the best cheap group 3 synthetic oils on the market.