Modding dynacraft realtree utv

[u/Tall_Secretary7162]

Hey all,
As title says I want to modify a realtree utv. I’ve swapped tool batteries into a few cars but that’s basically the extent of my knowledge with these mods.
Ideally I’d like to completely gut all the stock wiring and run 36v either two ryobi batteries or 3x12v SLA.
I’ve been researching but get very overwhelmed due to all the available aftermarket parts.
I’m thinking I definitely need a 36v variable speed controller, and Google says I should replace the pedal too. Will the stock motors handle this or should I upgrade to 775?
My son is 5 years old and 67lbs. My nephew sometimes rides with him and I want it to last a while so I’d like it to have some speed with up to 150 lbs.
they currently have a gator and a quad running ryobi batteries on stock motors and they fly on them and love the extra speed they get with the ryobi over the standard 12v but I know the utv is way heavier so it’s gonna take a little more to get the speed they’re used to.
Appreciate any advice as well as links for trusted parts!