You can do all the head-to-head comparisons you want, but it's the X factors that will probably decide it.
Red Sox X factors:
How big of a boost will we see from the following factors?
-JDM
-More aggressive approach
-Return to form from Betts and Bogaerts
How healthy will David Price be?
How well will our 'bridge to Kimbrel' hold up with Smith, Kelly, Barnes, Workman, Thornburg (?) et al?