What exactly does a jet kit do. I need some help. Also does anyone know what a 330 kit for my 300ex will cost and is it worth it

 

A jet kit, from what I have heard, increases wheel Horsepower by as much as 15%. Proper jetting is affected by elevation and engine mods, so the factory jetting for your quad might be perfect at sea level, but if you live 500 or 600 feet above sea level, the jetting is going to be off, so a jet kit is designed specifically for your altitude and engine mods. I've heard the 330 kits are awesome, but I don't know how much they cost.