4WD for PA? Why? Unless you live in the woods or on a private, non-plowed road, I can't imagine why you'd need the added weight, complexity and inevitable increased costs of operation & maintenance. Just my opinion, FWIW.
I'm in western CT at fairly high elevation, and have never gotten stuck in any of my 2WD, snow-tire-clad MBZs. Even my wife, whose snow-driving skills are somewhat suspect
, has never gotten stuck.
FWIW, I run Toyo Observes on the 500E and 300D, and Michelin Arctic Alpins on the TE.