Synthetic "Oil"

Just wanted to start this thread. I called the 1-800-nissan1 number and talked to one of the Titan specialists. I asked him about using the Mobil 1 in my truck. He sent my question to one of the powertrain engineers in Tennessee. The engineer reply was any approved oil (API starburst) is okay, even synthetic, but to keep the warranty valid, the required oil change interval must be kept up. This would mean changing every 7,500 miles with full synthetic, which would get expensive, but condisering the cost of every thing else, not unreasonable.
As background, I work as a Chemist in a lubricants lab where we do research on industrial lubricants. My boss, who has been in this area of research for twenty years, puts Mobil 1 in all his vehicles. He changes the oil every November, and changes the filter in May and tops off the oil level. He adds as needed, but only changes once a year. He does buy the longest oil filter he can find that fits his vehcile to give more filtration. He just sold a 1986 Dodge Caravan to his brother to use as a work van, 232,000 miles. They took it for a check-up and the engine was tested and still had over 90 % compression in all four cylinders. Two of them were at 95 %. Considering this is a four-banger engine pulling around a van and people, that is impressive in my book. He has gotten similar miles out of a Chevy Sprint, a Volkswagen Golf, and he has a Geo Metro with 100,000 miles that is going strong. I had a Chevrolet Silverado 1500 with 135,000 miles when I traded it in with no engine problems to report.
I will change my oil to Mobil 1 5W-30 when I get to 7,500 miles. A change at 1,000 will be done this week and another at 3,500 miles, each with regular oil. Then at 7,500 miles, Mobil 1 Synthetic. Just my views, but thought I would share!!