Bore up means larger bore on the cylinder.
Essentially what you are doing is increasing the bore (cylinder volume is (pi*r^2)*h). By increasing "r" (radius) you effectively square volume.
As for the ported or non ported, it's like ported pistols. Not really a good explanation but I'll try to go further.
With a ported cylinder you have "ports" for air to escape, this from what others say allows your pistons stroke to go all the way forward so your BB gets the most amount of "push" that it can.
With a non ported cylinder the theory is that, because you have such a long barrel the piston should complete the stroke before the BB exits the barrel therefore giving the maximum push to the BB.
There are different ported cylinders for different lengths of barrels so keep that in mind. From my research Prometheus offers a variety of ported cylinders to match specific barrel lengths.
ಠ_ಠLess QQ more Pew Pew
READY TO >> RACE