Outer Limits 4x4 Board

Hey I have a hydro assist unit set up on my truck it has the V6 comm pump runing it was wondering what mods people have done to theirs to get more out of them I have got a bit more by putting shims behind the return spring

any ideas ?? or who can i send it to toget more presure out of it ??

There doesn't look to be anything to drill out like most say because of the non return valve