Ics cxp ape upgrades

[ghostwalker]

I recently bought a ics cxp ape 2nd hand. Nownthe gun is flawless. New hop unit installed a fortnight ago, bodywork is in near perfect shape etc. It shouts straight and true. 

I got to field it yesterday for the first time and was fairly impressed (immsooilt as was shooting a krytac lvoa last year). 

Over the chrono it was hitting 315fps on a .20 and 258fps +/-2 on .28 bb's. The internals are stock. So I was thinking about a few upgrades. But I'm new to this gun. Was thinking a better spring to lift the fos just a little but I don't know what one. Then maybe a madbull 6.03 barrel and better hop nub maybe guarder clear or prommie purple. 

 

What would you fine folks suggest.