Originally Posted By: Char Baby
I have used the QS DEFY 5W30 in the Firebird in my signature. It's probably the single "smoothest/quietest" oil I have ever put in the engine in 35 years of ownership. I think the MaxLife did a better job on the oil drips.
I ran Defy in my old BMW last summer after about 30K on Maxlife.
The oil leaks might be a little worse with Defy, but measured consumption appears to be about the same.
I don't find Defy to be any smoother or quieter than Maxlife, but the four cylinder M42 is pretty smooth to begin with, if not what you'd call quiet, although most of the noise is from the headers and the rest of the exhaust, not the mechanical pieces.
Defy looks like a good oil at a good price.