I've had several EVO 300s but just bought a low mile 2020 Factory 300 that I've been taming or at least trying to tame. There is definately something to the Factory engine that is different. Looking at the parts lists the standard and Factory have the same cylinder and piston but a different ignition module so more aggressive timing I would guess. On my 2020 I've added Moto Tassinari carbon reeds V351B block with 3P412M reed petals, S3 long header pipe, S3 low compression head, clutch mod and gear shifter mod and 9 tooth countershaft sprocket. It's just now getting to where I want it but every once in a while it remembers it's a Factory and tries to kill me.😁