Short or long thread spark plug for polini evo 130?


Which is the correct spark plug for the new polini evolution 130 kit??? Short thread or Long thread??? In the instructions polini recomeds NGK BR10EG which is long trhread. I am a bit confused because on my vespa primavera I always used short thread spark plugs, and I used long thread sparks on my px200. 

Please long or short thread on this kit???

Long thread.