Is there a way to extend stash space in sp? has anyone updated pluggy or an alternative?

Also are portal scrolls fully removed?

I'm not sure if its even possible to add another act and if it is it would take more work than its worth. Although it would be interesting to see an act 6 that contained all the uber levels

Is there a maximum amount of avoid? Could I get 100% chance to avoid? or does it cap out at 75% or something