Paint and CO2 are the only things you'll need.
Detent rings or a barrel kit of some sort (Frantom, J&J, Lapco, etc.) would help, but anything beyond that is something you'll have to decide for yourself based on how the gun feels to you when you use it. That's a nice looking setup, and it should work well for you.
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"To love is to protect. To protect is to never betray."