This question goes out to BillGXE regarding his Oil Analysis Spreadsheet, but anyone familiar with his spreadsheet feel welcome to joing in. I just want to ask if BillGXE (or anyone else) has come to any firm conclusions from the data that has been collected on his spreadsheet. I find the information very informative, and thank BillGXE for making it available. Personally I think the data indicates that most brand name conventional oils perform as good as any of the more expensive synthetic oils during normal 3000 mile intervals. I've been one of these guys using Castrol GTX and Castrol Syntec Blend in recent years, and I have read a lot of the negative posts on Castrol oils. But looking at your data, Castrol holds up as well and even better than some of the more "ultra expensive" synthetic oils. I know people will say you can't compare different vehicles under different driving conditions , etc, etc......, but it looks to me like your data is pretty conclusive. I welcome any opinions that you may wish to share. Thanks again.