me again, i have a second lt80 that my daughter rides. i cut out/ sectioned out the baffle section fron the stock muffler then rewelded it back together. the piston is .50 over. the carb is jetted and running uni air cleaner. the bike runs great like this, do you think i would gain much with a/m exhaust?

hello, my son is outgrowing the power capacity of his stock kfx80. the bike runs stong and has never been cracked open. i am thinking of some arm ext and some internal mods. really would like to keep him on this bike until he will fit on a raptor 250 ish bike. what options do you think would work for me. thanks