how much of a dif will i feel wth ths kit?

[S.A.J]

hey yall,
well my 3rd gear on my06 foreman 500FE 4x4 went out n we gota tear it all apart 2 get 2 the transmission and we're doing it ourself n already got the motor outa the frame so i was thinking since we're already all in thr n gota take it apart why not go ahead n look into getn a big bore kit for it.i looked on the highlfter site n they got 2 big bore kits tht make it from a 475cc to a 506.5cc tht kits $206 n thn id hav 2 get it bored out yet.so baisicly my question/questions are how much is the ballpark figure on getn it bored out and how much of a diference will i b able 2 feel after.oh and is shaving the head an option too,n if it is how much is the price usualy for that?
i also looked for cams but i cldnt find one for the foreman500,only the ribicon500 which is 25ccs bigger so if n e one knos of a cam tht'll fit the foreman plz mention tht too,and if thrs sum thng else 2 do while its all apart tht wld b good plz tell me...
oh and plz excuse my gramer,i think i might txt 2 much,lol

thanks in advance,
S.A.J