How do I unlock rank 4 parts for the Zaku II (Char)?

Unlock and clear the "Char's Challenge 2" Extra Mission. To unlock the mission, you must max out your relationship with Char and have shot down 5000 or more units while piloting Char's Zaku II (combined total for all pilots). You must also clear the "Char's Challenge" Free Mission, which is unlocked after you clear Char Aznable's Story Mode and is playable for Char only (you're also restricted to one player and must pilot Char's Zaku II during this mission).

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Unlock and clear the "Seeking the Ultimate Zaku" Extra Mission. To unlock the mission, you must unlock and clear both "Zaku Lover's Club" Collection Missions, then read the terminal message received immediately afterwards. To unlock "Zaku Lover's Club 1", you must clear the "The Monster of Zeon" Collection Mission and shoot down 1000 or more enemies while piloting the Zaku II (combined total for all pilots).

To unlock "Zaku Lover's Club 2", you must clear "Zaku Lover's Club 1" and shoot down 3000 or more enemies while piloting the Zaku II (combined total for all pilots). To play "Seeking the Ultimate Zaku", you must shoot down 4000 or more enemies while piloting the Zaku II (combined total for all pilots). Both of the "Zaku Lover's Club" missions and the "Seeking the Ultimate Zaku" mission require you to pilot the Zaku II only.

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Unlock and clear the "Char's Offering" Friendship Mission and read the terminal message you receive afterwards. To unlock the mission, you must max out your relationship with Char and complete the first two stages of the "Earth Conquest" Friendship Missions (unlocked when you join the Principality of Zeon). More.

Unlock and clear the "The Mightiest Surface Weapon" Extra Mission. To unlock the mission, you must clear the "Earth Conquest 3" Friendship Mission and the "Soldier's Battlefield 4" Free Mission. You're required to pilot the Zaku Tank during this Extra Mission.

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