I run a VM20 on my stock cylinder with a mlm pipe. I think I have a 165 main jet in there and a 17.5-22.5 idle? With a screen air filter. If you’re using the stock pipe then adjust your jetting a little down.
The VM20 works fine but to be honest the stock carb works fine as long as you have the stock cylinder. Just more future proof for if you throw a kit on it. A little more responsive but its louder too.
You have to get a new intake pretty sure and while you can stretch the boot to fit the carb somewhat, I just ended up deleting the air box. Have to rig up something to mount one of the side covers though. Oil injection still working greats with the MLM intake