so I just started up in a zone and got the following on mayhem 3:
assault rifles and sniper rifles deal -50% less damage but deal 50% more damage with pistols, SMGs and shotguns. Player takes deal 50% less damage with action skills and grenades but 35% more damage with guns. Players deal 70% less damage with normal bullets but player deals 70% more damage with all elemental damage. and last but not least: player regens 70% less health and shields but gains 16% move speed, fire rate and reload speed.
this combo turned on god mode for me as I mostly use elemental guns! if these stack its a crazy 155% extra damage with elemental pistols, SMGs and shotguns! and to make things sweeter I am a zane violent momentum build so the extra move speed is just extra damage in the bank!
anyways the modifiers are GREAT, most of the time you can just keep rerolling till you get something that buffs your damage by 50-70%+ and then just nuke anything you meet!