You can only fill those cylinders to 250 bar if you have a reg fitted
My HW100k will have about 5 fps spread , anti tamp has been taken out when I had a service , set up and all O rings replaced for the price of £95
Sorry I just don't see it ,£800 for a new hw100 then spend half of that again on a tune ,when this gun is already one of the best PCP's if not the best sub 12