Act3 ? i'm not sure i'll play long enough to ever see the end of Act2
Already 50 hours invested in that character and i'm not at the end of Act1 yet.
There are plenty of really strong >130 enemies... but they shouldn't be a problem since they should only appear when you're at ridiculous levels with ridiculous skills and power too.
Well in the bestiary, there are extremely few +level 130 monsters, in fact you should meet none of them unless you really want to (they're gods being summoned by a wish and for some reason you want to attack them after that).
Out of the special (and fortunately optional) Void dungeon that boost the existing levels of every monsters by a lot in it.
monster levels apparently is not based on your own or your skills, but the higher level you are, the monsters you'll encounter in the wild will be selected from the higher level ones too according to wiki.
Though maybe if you count the summoned escorts of the world map encountered merchants if you decide to attack them, i remember seeing a level 100 guy while i was rather low level at the time, so maybe those get even stronger with you.