i think i can help you out with this, since i have the same gun. here is what i got along with what is currently being installed:
Gearbox Internals:
Prometheus Tightbore
Prometheus Spring Guide
Prometheus Hard Piston
ARS POM piston head
ARS Cylinder head with attached sorbo
Prometheus Air nozzel
Reinforced selector arm (Very important IMHO)
Guarder steel cutoff lever (very important IMHO)
Guarder Infinite Torque Motor (gives you instant trigger response)
G&P reinforced mechbox (not really needed)
KM TN Hop-up dial screw (again, not really needed)
M110 spring
Externals:
G&P RIS
Mount your scope on this along with flashlights and everything else for night games and cool shit like that.
For the bipod, i truly recommend against it. It will just add more front weight and is not needed at all.
That setup should give you around 400 fps and will give you ultimate longevity and performance. For scopes, i use a pistol scope with long eye relief. I mount it on my front rail. I use an
NC Star Pistolero Series of scopes. Perfect eye relief, adjustable for wind/elevation and adjustable magnification from 2-7x. Dont get the illuminated reticle, its just a waste of money.
You dont need more than 6 lowcaps. I dont even go through all 6 in an entire day.
Hope that helps dude