Not sure if this is invalid because I am only lvl 53, but here are some changes bolster made after I upgraded mods.
All Makeb 140 mods before - Crafted 156 mods after (no other changes)
Expertise changed from 1936 to 1913
Health 27944 to 30203
Bonus Damage 773.6 to 769.3
Bladestorm max 3637 to 3628
So, after the upgrade everything went down except health.
*sorry, formatting got messed up
Sorry I should have stated that is for lvl 55... Not pre 55
Pre 55 is more tricky as having the best gear you can get for your lvl can make you go backwards in stats... A bit like using 180 PVE gear at lvl 55
Also the closer you get to 55, the less bolster you seem to get