diff --git a/.luacheckrc b/.luacheckrc
index 2e903fee..8d8ff494 100644
--- a/.luacheckrc
+++ b/.luacheckrc
@@ -1497,6 +1497,7 @@ stds.ecs = {
         "GetUICameraInfo",
         "GetUITextureKitInfo",
         "GetUnitHealthModifier",
+        "GetUnitManaRegenRateFromSpirit",
         "GetUnitMaxHealthModifier",
         "GetUnitPowerModifier",
         "GetUnitSpeed",
@@ -2767,6 +2768,7 @@ stds.ecs = {
         "WOW_PROJECT_WRATH_CLASSIC",
         "-----------------------------------------------------> Enums",
         "LE_EXPANSION_BURNING_CRUSADE",
+        "LE_UNIT_STAT_SPIRIT",
         "-----------------------------------------------------> GlobalStrings",
         "CLOSE",
         "DEFENSE",
diff --git a/Modules/Data/Constants.lua b/Modules/Data/Constants.lua
index 66fa6185..40045ef4 100755
--- a/Modules/Data/Constants.lua
+++ b/Modules/Data/Constants.lua
@@ -284,6 +284,46 @@ Data.Aura = {
         [25894] = (ECS.IsClassic and 1 or nil), -- Greater Blessing of Wisdom rank 1
         [25918] = (ECS.IsClassic and 1 or nil), -- Greater Blessing of Wisdom rank 2
     },
+    PowerRegenPercentModifier = {
+        [Enum.PowerType.Energy] = {
+            [13750] = 1, -- Adrenaline Rush
+            [58427] = 0.3, -- Overkill
+            [66203] = -1, -- Steam Blast
+            [69470] = -1, -- Heat Drain
+            [70385] = -1, -- Abomination Vehicle Power Drain
+            [72242] = -1, -- Zero Power
+            [1231381] = 0.26, -- Feral Dedication
+        },
+        [Enum.PowerType.Mana] = {
+            [5419] = (ECS.IsTBC and -0.11 or nil), -- Travel Form (Passive)
+            [5421] = (ECS.IsTBC and -0.11 or nil), -- Aquatic Form (Passive)
+            [12051] = (ECS.IsClassic and 15 or nil), -- Evocation
+            [18371] = (ECS.IsClassic and 0.5 or nil), -- Soul Siphon
+            [24705] = (ECS.IsClassic and 0.25 or nil), -- Invocation of the Wickerman
+            [27747] = -1, -- Steam Tank Passive
+            [29166] = ((not ECS.IsWotlk) and 4 or nil), -- Innervate
+            [33948] = (ECS.IsTBC and -0.11 or nil), -- Flight Form (Passive)
+            [34754] = (ECS.IsWotlk and 0.16 or nil), -- Holy Concentration
+            [40121] = (ECS.IsTBC and -0.11 or nil), -- Swift Flight Form (Passive)
+            [42514] = 1, -- Arcane Surge
+            [49307] = 1, -- Full Mana Regen
+            [51623] = 5, -- Sholazar Guardian Heartbeat
+            [63724] = 0.32, -- Holy Concentration
+            [63725] = 0.5, -- Holy Concentration
+            [456195] = 4, -- Innervate
+            [468466] = 1, -- Unmaking the Simulacrum
+        },
+        [Enum.PowerType.RuneBlood] = {
+            [50469] = -0.5, -- Rhythm of the Fallen
+            [50779] = 1, -- Blood Rune Mastery
+        },
+        [Enum.PowerType.RuneFrost] = {
+            [50469] = -0.5, -- Rhythm of the Fallen
+        },
+        [Enum.PowerType.RuneUnholy] = {
+            [50469] = -0.5, -- Rhythm of the Fallen
+        },
+    },
     SpellCrit = {
         [24907] = ((not ECS.IsClassic) and 5 or nil), -- Moonkin Aura
         [29177] = 6, -- Elemental Devastation Rank 2
diff --git a/Modules/Data/MP5.lua b/Modules/Data/MP5.lua
index 5ea8de85..ede12066 100755
--- a/Modules/Data/MP5.lua
+++ b/Modules/Data/MP5.lua
@@ -74,48 +74,61 @@ function _MP5:GetMP5ValueOnItems()
     return mp5
 end
 
-local lastManaReg = 0
-
 ---@return number
 function Data:GetMP5FromSpirit()
-    local base, _ = GetManaRegen() -- Returns mana reg per 1 second (including talent and buff modifiers)
-    if base < 1 then
-        base = lastManaReg
+    local regen
+    if ECS.IsClassic then
+        -- GetUnitManaRegenRateFromSpirit uses TBC formula in classic
+        local _, spirit, _, _ = UnitStat("player", LE_UNIT_STAT_SPIRIT)
+        if spirit < 50 then
+            regen = 0.25 * spirit
+        else
+            if classId == Data.PRIEST or classId == Data.MAGE then
+                regen = (12.5 + spirit/4)/2
+            elseif classId == Data.DRUID and (not DataUtils:IsShapeshifted()) then
+                regen = (15 + spirit/4.5)/2
+            else
+                regen = (15 + spirit/5)/2
+            end
+        end
+    else
+        regen = GetUnitManaRegenRateFromSpirit("player")
     end
-    lastManaReg = base
-
-    return DataUtils:Round(base * 5, 2)
+    return DataUtils:Round(regen * 5, 1)
 end
 
 -- Get mana regen while casting
 ---@return number
 function Data:GetMP5WhileCasting()
-    local _, casting = GetManaRegen() -- Returns mana reg per 1 second (including talent and buff modifiers)
-    if casting < 0.1 then
-        casting = 0
+    -- Returns mana reg per 1 second (including talent and buff casting modifiers)
+    local _, casting = GetManaRegen()
+    local modifier, mp5BuffBonus, periodicMana = Data:GetMP5FromBuffs()
+    -- castingModifier = min(1,castingModifier + _MP5:GetTalentModifier() + Data:GetSetBonusModifierMP5()) -- capped at 100%
+    casting = casting * 5
+    if ECS.IsClassic then
+        -- in classic GetManaRegen doesn't account for mp5 from items nor buffs
+        casting = casting + Data:GetMP5FromItems() + mp5BuffBonus
     end
-
-    local castingModifier, mp5BuffBonus, periodicMana = Data:GetMP5FromBuffs()
-    castingModifier = min(1,castingModifier + _MP5:GetTalentModifier() + Data:GetSetBonusModifierMP5()) -- capped at 100%
-    local mp5Items = Data:GetMP5FromItems()
-    casting = (casting * 5) + mp5Items + mp5BuffBonus * castingModifier + periodicMana
-
-    return DataUtils:Round(casting, 2)
+    casting = casting * modifier + mp5BuffBonus + periodicMana
+    return DataUtils:Round(casting, 1)
 end
 
 ---@return number
 function Data:GetMP5OutsideCasting()
-    local mp5FromSpirit = Data:GetMP5FromSpirit()
-    local _, mp5BuffBonus, periodicMana = Data:GetMP5FromBuffs()
-    local mp5FromItems = Data:GetMP5FromItems()
-
-    local totalMP5 = mp5FromSpirit + mp5FromItems + mp5BuffBonus + periodicMana
-    return DataUtils:Round(totalMP5, 2)
+    local base, _ = GetManaRegen()
+    local modifier, mp5BuffBonus, periodicMana = Data:GetMP5FromBuffs()
+    local totalMP5 = base * 5
+    if ECS.IsClassic then
+        -- in classic GetManaRegen doesn't account for mp5 from items nor buffs
+        totalMP5 = totalMP5 + Data:GetMP5FromItems() + mp5BuffBonus
+    end
+    totalMP5 = totalMP5 * modifier + periodicMana
+    return DataUtils:Round(totalMP5, 1)
 end
 
 ---@return number, number, number
 function Data:GetMP5FromBuffs()
-    local mod = 0
+    local mod = 1
     local bonus = 0
     local periodic = 0
     local maxmana = UnitPowerMax("player", Enum.PowerType.Mana)
@@ -127,7 +140,7 @@ function Data:GetMP5FromBuffs()
             bonus = bonus + (Data.Aura.MP5[aura.spellId] or 0)
             bonus = bonus + (Data.Aura.PercentageMp5[aura.spellId] or 0) * maxmana
             periodic = periodic + (Data.Aura.PeriodicallyGiveMana[aura.spellId] or 0)
-            mod = mod + (Data.Aura.AllowCastingManaRegeneration[aura.spellId] or 0) -- assuming buffs stacking, to be investigated
+            mod = mod + (Data.Aura.PowerRegenPercentModifier[Enum.PowerType.Mana][aura.spellId] or 0)
             if Data.Aura.IsLightningShield[aura.spellId] and Data:IsSetBonusActive(Data.setNames.THE_EARTHSHATTERER, 8) then
                 bonus = bonus + 15 -- 15 MP5 from Shaman T3 8 piece bonus when Lightning Shield is active
             end
@@ -153,7 +166,7 @@ function Data:GetMP5FromBuffs()
         end
         i = i + 1
     until (not aura)
-    return min(mod,1), bonus, periodic
+    return max(mod,0), bonus, periodic
 end
 
 ---@return number