MLM doesnt have mass-production scale. everything is hand made. clean welds, flat surfaces, powder coated, made+designed in USA, etc
I've made intakes out of stock exhaust headers and then spigot mounted a carburetor. sure, i saved money on the intake, but it was ugly and i spent alot of time messing with it to make it work.
its a balance of time and money. i used to have the time and a garage, now i don't; so i plan it all out before i even turn a wrench.
if you're gonna stick with stock or 50cc, 15mm carb and intake is perfect. if you want a kit, best to go up to 18mm-21mm... but you cant really tune a carb that big on a stock A3. plan now and buy only once.