Why not just remove the front rotors and calipers, and turn it into a Yamaha KT100 ?
Shifter karts are very complicated for a brand new karter, and will be a very difficult to learn how to tune, plus they are a handful to drive if you’re a new driver.
The KT100 clutch engine will have enough power to get you excited, cheap to maintain, and will teach you how to become a good driver.
But if what you really want is shifter karts then I will respect that.
Just keep in mind that a huge amount of new karters that jump into shifter karts do get very frustrated, very quickly when stuff always goes wrong, unless you buy a fairly new and super expensive engine package and have someone helping you tune.