hey mate, same kinda thing i found with my gtr stock everything except for zorst, full boost by 4000rpm atleast, not a reall kick in the back either... untill i boosted her to 15pound, made a world of difference,cam gears are going in atm so hopefully that will help lag.
but yeah adjustable actuators on stock turbos not so sure, maybe put factory ones on and save ur self time mucking round.
ball bearing turbos help too....