Uh, is it just me or do people have a serious problem with reading comprehension?
Can create Dwarven armor and weapons at forges, and improve them twice as much.
If you don't have the perk for Dwarven armor, then when you upgrade it, it upgrades by, say, 20. When you have the perk, your upgrades to Dwarven armor are 40.
This is irrespective of the "label" of upgrade (e.g.: Flawless), which is based on your Smithing skill.
This hits you full-force when you're sitting on 100 Smithing skill, and you have a set of Shrouded Armor and Glass Armor in your inventory. There is no perk for "LEATHER SMITHING", so your awesometastic super backstab Shrouded Armor can only be upgraded by HALF of the Smithing upgrade to your Glass Armor.