Racing Exhaust SIP ROAD "Ban.. ..ana" for Vespa 90/R/SS/100 /125/PV/ET3 steel, chrome, large exhaust manifold

Racing Exhaust SIP ROAD "Ban..

..ana" for Vespa 90/R/SS/100
/125/PV/ET3 
steel, chrome, 
large exhaust manifold it suggests a bigger carburettor 25mm what do you suggest I'm keeping it standard 125 for now thanks .