What follows is a collection of mechanics and formulas for various aspects of World of Warcraft Classic Burning Crusade as they pertain to feral druid cat form DPS. These formulas are being presented here to assist theorycrafters, as there is a great lack of quality information available on the underlying game mechanics. All formulas listed below reflect a level 70 character and (when relevant) a level 73 (raid boss) enemy.

Cat Form Damage Formulas (as of TBC Patch 2.5.2.40488)

White attacks (melee_damage): (768 + attack_power) / 14
Mangle: melee_damage * 1.6 + 264
This formula is well-documented, and matches the in-game tooltip value. This formula gives Mangle an overall attack power scaling value of ~0.114 * AP.
Shred: melee_damage * 2.25 + 405
This formula is also well-documented, and matches the in-game tooltip value. This formula gives Shred an overall attack power scaling value of ~0.161 * AP. Note: Shred damage is affected by the Mangle debuff (x1.3) multiplier.
Rip (5 Combo point): attack_power * 0.24 + 1553
This formula was determined via direct testing, and does not match the in-game tooltip value. At this time, I am unable to find any documentation from the game developers on this deviation/buff from the tooltip value. The correct 4 combo point formula is: attack_power * 0.24 + 1272. Rip also ticks six times over 12 seconds, so the value of each tick can be calculated by dividing the total damage by six.
Ferocious Bite: attack_power * 0.25 + 941
This formula was determined via direct testing. In addition, extra energy consumed by Ferocious Bite converts to extra damage using this formula: extra_energy * 4.1.

Note: the above formulas represent the average damage of each attack. Melee, Mangle, Shred, and Ferocious Bite damage are actually represented in-game as a narrow range of values.

Cat Form Mana and Mana Regeneration Formulas

Mana: 2370 + (intellect – 20) * 15 + 20
This formula was determined via direct testing.
Mana Regeneration (Every 5 seconds): (0.001 + (spirit * Math.sqrt(intellect) * 0.009327)) * 4.43
This formula was estimated based on the developer-provided formula for mana regeneration, and reflects the slightly lower mana regeneration values observed while in cat form compared to caster form. At this time, I am unable to find any documentation from the game developers on the exact coefficient for cat form mana regeneration. Note: this formula only applies to mana regeneration when not casting, and may not be relevant depending on the frequency of powershifting used.