Something to add about using the longer valve, keep in check the outlet end of the valve. Even though you modded the follower in the bb tube (which I have done long ago to mine as well) and took a hair off the length of the valve, the valve will still make contact with occasional bb's. This will dent the end of the valve and could cause the valve to eventually stick open. Although, it is easy to remedy with a file.
What is most important about the high flow MT valve is just that. It is high flow. The length of the valve does little if anything to enhance performance IMO.
Also a final word of advice I can give you is that if you are using a high flow valve, I suggest you port out every opening you can through the WHOLE air supply as well to optimize the use of the high flow valve. This should especially be done with the Blackbird type magazine.
If you are using HPA instead of CO2, remove the filter screens.
