Just think about it how you would in upgrading a Sypder. More info can be found:
Undoubtedly though, your first upgrade should be a new barrel. Depending on what you really want from your barrel will determine which you will buy (i.e. versatility= freak, equation ms pro, or the new aradus barrel <--- most versatile of them all).
You should also consider getting an electric revy like the 12V viewloader or the ricochet.
'05 Proto Matrix
Techna Finger Job Style Trigger, CP Dust Black 12" Pro Barrel, CP Dust Black Twist Lock Feedneck, STD Industries Proto LPR, Orange SAM Proto bolt with Tophat Mod, Proto Low Pressure Bolt Rear Cap, Tadao M3 software, Hybrid Red Lady Grips, Black CP Black Razor Drop, Pure Energy 72ci 4500psi HP Peanut tank, Red Halo B with V35