[lurkingknight]

Why do you want such a long barrel? Why would you want a longer barrel anyways, aside from slightly longer to accomodate the realistic length suppressor of a p90? What are you trying to get out of it? Should you not care regardless of what anyone says and still choose to go with that length, an end ported or full cylinder will work.

why would you change out the gearbox that's a decent one for a shit one? What's wrong with the shell? Changing shells in addition to mixing manufacturers can make bad manufacturing tolerances worse, and can make your gun perform like shit.

Changing out complete gearboxes will not give you a stable platform to install an R-hop on. You need to check/service/upgrade compression components to eliminate as much air leakage as possible to get the best results from the r-hop.. or any hop up system, even stock.

V6 uses a long motor.

Properly service/upgrade the existing gearbox by checking compression, upgrading what's needed. Don't blindly throw money at it.

Weaknesses in p90s is the trigger contacts, they're not super hard to replace but can be a pain sometimes to source and nothing works quite like original... a basic mosfet can help eliminate the need for that.

Angle of Engagemet fix. If you've managed to read up a little on r-hop, you can manage to read up on AoE. It's a 6$ fix. On second thought, if you've read a little about r-hop, read MORE about it too, find out why it works, how it works and why things should be done certain ways before just throwing money at it blindly.