Vespa PK 75 s needs new carb

Hey! I've got a Vespa PK 75 with a broken carb.  The metal part that connects to the tube where the clamp goes has broken. I don't know how this happened but now it's sucking in a load of air and this has really affected the performance. It's just the standard carb but now I'm thinking this is a good opportunity to upgrade and improve the performance.

What carb can you recommend me to give the best performance?

I've been looking at this one: Art.Nr. 41000000. Would a 25mm be suitable for my 75cc or will it choke it up?

What does rubber or plug connectors mean???

Thanks for you help.

Phil. (Madrid)

I think that 25mm is too much (it may be suitable for a 125cc), in my opinion 19 or 20 mm is the right choice.

Greetings. Oscar

I have a pinasco 102 and a 20mm carb [;)]  works just fine