Keith…you make some good points especially about the cables, but what makes you think that the Xterra is not front heavy with the motor in the front ? 54% front vs 46% rear are it’s specs. In general, all rwd cars do better in snow if weight is bias to the rear. and 2 to 300 lbs is minimal, little more than one and a half passengers making the distribution close to the magic 50/50 which would enhance handling.
Obviously, loaded with gear in the back would help either instead or in addition to the bags, depending upon the total load. I have gone as high as 500lbs in compact trucks with excellent results. as long as weight is kept over axle or in front by SUV seat back or truck bed and not behind. Severe negative affects on handling doesn’t happen if this little weight is carefully placed.