So here's what I found . . .

Cables seems to have a lower profile, and being that the X3 doesn't need that much help (really we're just pacifying the Fuzz), better to be safe for the car. The S classification covers cars that don't have a lot of clearence around the tire, so I ordered cables that fulfill this requirment. Does the X3 require S class? I doubt it - I could fit full size bread boxes ontop of my tires in the wheel well. But if this is the lowest profile, I'll take it to keep BMW from freakin out.

I'm not sure if I trust cables that do not require tighteners. Some models do not and, well, chains and cables stretch, so I went with a tightened version that I have more tightening control over.

I got the SCC Super Z6, which claims to work with anti-lock break systems. $80 a pair, and I'll figure out if they are more effective on the front or rear tires. I suspect the rear. (I have control over correcting the front tires, but if I lose traction in the rear, I'm FUBAR - all wheel drive or not.)

In the past I've had chain dissasters (chewed up a SAAB and a Jetta). Now I know not to hit 70 mph and everything should be alright. Side's, if'n I find myself needing chains at all in an X3, it's because something serious is happening.

BTW, I found the thread under search - great advice. Thanks.