Here we go with the mobil1 bashing again. Sigh. Seriously you guys do realize there are different blends for different weight oils correct? With that being said, PORSCHE recommends Mobil1 0w-40 in all their cars. Take into account, the minimum replacement price for most of these engines is $15k. Do you seriously think the company what has tthe best reliability ratings out of ANYONE on the planet right now, does so with crap oil in their warranty-guaranteed engines? I have replaced ONE engine in seven years due to oil failure, as it turned out the lady thought she only had to change the oild every 25k lol, and that engine made it to 50k before spinning the int. Shaft out the block. BDVT, you have experienced a catastrophic engine failure at the hands of mobil1, and that sucks. But there are several thousand 600+whp 911 turbos out there who have never experienced problems, and run 0w-40, which for the record I run in all my cars, and have for the last 6 years. I would agree that most the other blends are gov mandated detergent crap, as is most everything. Most synthetics are manufactured to the SAME specs (its called base stock, google if you don't believe) with the important stuff added later, like phosphorous, zinc, etc. How much of the good stuff depends on how they want to sell it.
Personally, owning nothing but turbo cars and driving a total of maybe 15 miles a day, I change my oil every 2k miles. Reason= contamination. Extra fuel from the warm up phase, and moisture build up from never getting the car warm enough long enough to vaporize it being the key reasons here. I also use bg107, which is basically a can of more o the same additives used to bring the oil to spec in the first place.