The word "siping", as a verb, means "to make many shallow cuts in the contact sufface of a perfectly good tire". {my definition, of course}

It may improve traction in some cases, but it absolutely accelerates tire wear and may void your warranty.

As to the term "all-wheel drive" and "4 wheel drive", they mean exactly the same thing.

I'm sure there will be a round of posts desputing that but so be it. The fact is that each term carries baggage from the characteristics of the 4WD systems used by companies that use these terms.

The difference is in the systems, not the terms.

4 wheels drive systems can be "full time" or "part time" to start with, but subtly differences are many. Subaru does not use a transfer case but separates power to the drive axels in a specially-designed transmission. It works very well in family transportation but is not competetive in "hardcore" off-road applications.