In this two-part video, Kiyomizu upgrades a SIG Air ProForce MPX-K Sportline AEG by installing an Inazuma motor and a Perun AB++. He begins by testing the gun’s standard performance before replacing the motor with the Inazuma model and conducting another test. Next, the Perun AB++ is installed, which requires extensive disassembly of the gun. The process involves removing the stock, handguard, barrel, receiver pin, and various other components to access the gearbox, followed by extracting the spring and gearbox screws.