I've been using Millers Nanodrive oil for the past 2 years, initially on my Subaru and now on my 911. This oil is worth the money on the tin, it's highly recommended by performance tuners up and down the country, who have seen notable differences on highly tuned cars.
Hartech are probably the best independant specialists for Porsche in the country and they have pioneered the engine modifications for the 997's common engine flaw, cylinder bore scoring. They recommend this oil to anyone who owns a 997, as it has better lubrication of the parts within the engine. After switching to this oil, the immediate change I observed, was the fact that my engine oil temp was reading almost 10c lower. Now, the problem of the bore scoring affecting the 997 was due to the inefficient cooling on one bank of cylinders, 4,5,6. So, anything to add in cooling this area is a godsend to the car.
Some things in life really are worth the money you pay for them. What you have to remember is that, oils like Millers and Silkoline are motor racing oils, so a lot of research and development has gone into them.
