Does that help^? E46 ///M comparison test against the B6 S4.
Both perform very well and is just a taste of what you might expect with either car.
I can't really give you a verdict on either because I'm not fond of the SMG from BMW on that particular series and the B6 is not really a tempting matter for me either. Both are excellent machines though.
EDIT: not to be flamed, but I am surprised that the S4 did the track 1 second faster than the M3.