Eses proprietary gears I believe(4 gear system) and they're fine.
Sorbo pad isn't necessary as the gearbox is really strong and you wont be running crazy RPS. Also the piston is oversized so not sure how that would affect the sorbo. You also dont want to lose volume in the cylinder which is what the sorbo will do.
I would get the S&T midcaps they work great.
Springs are standard aeg springs.
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