take the hammer spring and with a pair of needle nose pliers roll the bend down to the coils,this will make the hammer hit harder.
next is take the valve out and cut exactly one coil of the valve spring off and stretch the spring apart slighly to its original size b4 you cut it.teflon tape the threads with one wrap of teflon tape JUST on the threads so it wont get in the valve and interfere or prevent the valve from seating all the way.
carefully open up the ports with the next size up drill bit
now while you have the valve out replace the seal for the co2 cart.
also taper the valve stems brass shank for the spring slightly in a drill with a file and then slightly bevel both sides of the end under it.dont go nuts just round it slowly and cool it every few seconds in a cup of cold water or you will fry the stem seal if you get it too hot.
when you reinstall the gun back together make sure to lightly tap the brass tube in,theyre real easy to bend.
these are simple easy to do mods that will increase your power with out sacrificing carts for a few good shots.