I've been really pleased with the RLI BioSyn 0w-30 oil that I've been using in the car for the past 6.5 months and just over 5,000 miles. I think since I received such a good UOA from Blackstone with the Pennzoil Platinum 5w-30 last year after 5,000 miles, I'll keep this RLI Renewable Lube oil in the '06 Camry for a total of 6,000 or 7,000 miles and/or 8 or 9 months before changing out the oil. Any objections? The Camry LE 4-cylinder now has 24,710 miles on it, and the RLI oil has just over 5,000 miles on it as of today. At the next oil change, I'll get a Blackstone UOA on the RLI to compare it to the PP. My second question concerns the high acidity of the Renewable Lubricants Bio-Syn oil. Since RLI is suppose to work a little like Auto-RX and clean out your engine and since my '06 car is so new and only has 24,700 miles on it, would it be better for me not to use RLI for two consecutive oil changes? Six months ago, I put into the Camry a total of 4.25 quarts of RLI 0w-30, so I have another 4.75 quarts of RLI oil left over and ready to go into the Camry for the next oil change, but I'm thinking that might be too much cleaning--and too much acidity for too long a period for such a new engine? Can all that acid have a bad effect on the rubbery-like gaskets and sealants? Maybe I ought to put Amsoil SSO into the car next, and save the 4.75 quarts of leftover RLI for another time--say 3 years from now? Sound like a good plan? Also, because of the high acidity, is it recommended that RLI be used more for older engines than newer engines? I would like my car to last at least 15 years. Schucks, I suppose 20 years would be nice too.