You are fine for your defenses. 45% is soft cap, doesn't matter if it's 45 or 700% defense, Soft cap is 45. Set number for mobs is 50, minus 45 is 5% chance for them to hit base. With no additional buffs/internal buffs for them.
Barrier offers you Res though, but SR also has a increased Res buff as you get lower HP, add in that recipe set that does same... Barrier is more team friendly for your squishier folks.
Scrapper - Dark Melee - Super Reflexes.mxd