Aggrowise:
Courageous mainpieces have 34 more hate increase and 14 more hit rating then fearless. (lol @ anyone bringing up the health regen)
Fearless mainpieces have 175 crit rating and 145 crit damage rating more then their courageous counterparts.
Look at those numbers again and tell me where courageous has more aggro.
Don't be fooled by the armor on courageous.
In the end courageous mainpieces have only 28 more armor which at those mitigation levels (+/- 59%) with the deminishing returns on armor-->mitigation is nothing. The only reason to ever go for courageous mainpieces on a guard is if you want the constitution. (Demigod and Archfiend come to mind)
the T4 set with highest aggro for ANY soldier is: Fearless mainpieces, Indomitable feet-belt-hands, courageous wrists-shoulders.
Only deviations for this is that you could argue the indomitable head has more aggro for a DT (doubt it tbh) and Courageous hands might be a better choice for guards (doubt it again: 60crit vs 23hate).
Now a guard could use courageous small pieces since his loss in aggro will be minor and he gains some constitution. Apart from that the combination I mentioned above is the highest aggro set for any soldier.
Anyone telling you crit/critdmg does not matter on a guard should have themselves checked out.
EDIT: if you want the hate so badly get the wrists, hands, rings and neck from the unchained dungeons. There is much more to be gained there.