Is it really recommended to get snow tires? I live in eastern PA.

Snow tires MUST be installed on the DRIVE axle - in this case the front axle .. It is imperative to have very good tire tread “depth” on ALL tires while driving on snowy roadways! Even a 1/2 worn out tire will compromise traction when driving during inclement weather conditions .. Tread depth is the key - tires designated for winter driving conditions will greatly improve traction - some folks prefer to use winter / snow tires on front AND back of vehicle.

Yes, go with 4 snow tires; 2 on the front will expose the non-equipped rear wheels to fishtail; 2 on the rear alone will prevent needed traction in the front.