changing typhoon carbs

just wondering what would be best a 20.5mm or 25mm. the engine is standard at the mo but plans are that soon she will be getting lots of work, so whats the better plan, standard size then get a bigger one later or bigger one straight on?

 

go for a 25mm if ure doin more to it mate then upjet the carb if needed

 

cheers very much bud

 

no worries mate