Who said doesn't add horsepower akuma.. it does.. (in the minds of the ownerlah.. hehehe)
lighter clutch, flywheel = less hp loss through drivetrain.. so on wheel hp will improve. Mine has a drivetrain loss of 30hp on the stock g/box (according to my prev. dyno resultlah, as inaccurate as it may be), although I've seen some with lightened bits losing only 20-27.
I don't know about anyone else, but from what I know, the dyno machines cannot accurately measure engine hp, only est. trough calculation of friction and stuff.