I have an idea for an experiment. Let me know if you think this would be a good idea. I have a '96 Chevy Caprice that gets driven 18,000 miles a year. I am considering running Supertech 5W30 for 1,000 miles, then sampling and draining out about a quart, then inserting another quart of Supertech 5W30. Send off the sample for analysis, rinse wash and repeat. Kinda' the same way that 3MP is doing, except using The Lowest Biddger among retail conventional oils. End experiment when Blackstone says to run away screaming. If experiment hasn't ended by 7500 miles, change oil filter at that point. I realize that I'll be using a different formula for every top-off due to the way Wal-Mart works, but if the oil makes it, it will prove that even the "worst" oils are good for substantial drain intervals if you emulate 3MP. I also realize I had sodium issues on my last UOA. I would not bother with the experiment I'm mentioning unless my newest sample indicated that this problem had abated. I had my compression tested, and it came out fine. So, whatcha' think?