WE Katana upper receiver help
 

First of, I have a we katana raptor version...
It is actually very nice gun. A lot of weight in the front though. (Front heavy)
I am trying to look for an upper receiver for it. So that when I play indoor I can switch my upper and have a 350 fps on it, and switch the back to the 400 fps upper. I don't know what kind of receiver to buy because it has 2 pins in the katana due split gear box. plus I want to have a Daniel Defense mfr rail paired with the new upper receiver. Any recommendations to what kind of upper I should get?

You can just buy another cylinder and swap them out. Cause that's what the katana's made to do. But I guess if you want the different rail system, then I suppose you're kinda stuck with having to have two separate uppers