AMGDave

The M-1 TDT formula is, oddly, slightly less expensive - which makes no sense, since Delvac-1 is *more* expensive. But when Mobil puts the same stuff in a different container, they reduce the price. Very weird.

Anyway, you can get a 4-quart (1-gallon) jug of M-1 TDT oil at most Wal-Marts for about $22-$23, or individual quarts at AutoZone, etc for ~$6/qt. Many of the newer oil specs are geared toward lower emissions, and removing additives that could affect some of the newfangled catalysts. Some of the diesel oils are more robust and have been compromised much less, IMO, at least so far. Check out the attached product guide from Mobil... note that D-1 may be the only Mobil synthetic that still has ZDDP additive.

Very thin oils like 0W-30 can help manufacturers meet EPA regs for fuel economy, and they can also increase peak HP a tiny amount, but often sacrifice engine longevity to at least some extent. While I might use them in a race engine that would get periodic rebuilds, I wouldn't want them in my street-driven engines that I want to last 500kmi...! I used M-1 10W-30 in my race bike ('97 GSX-R) for a while but got nervous due to the odd smell of the oil, and noisier engine operation. All went back to normal when I switched back to M-1 15W-50. YMMV, etc...

Garfunkle_W124

You really want to know what's wrong with your car? Put the damn AMG kit on it and it will run like new!

CDP

not only that - it'll look like new as well!