My Vespa GT200 current setup is:

Malossi tuning kit 282cc

Crankshaft Conversion Kit KÜBLER Racing 278/282
Cylinder Head: MALOSSI V4 Head

Carburetor: KEIHIN CVK 301E

main jet: 102

Filter box: non modified stock

Filter sponge: malossi red sponge
Spark plug: CR8EKB
Primary gear: 17/44 Polini
Secondary gear: 16/42 Malossi
Variator: piaggio stock 300cc
13,6g rollers

Belt: Dayco Kev l 835 mm w 22,6 mm h 14 mm (GTS 250-300)

Clutch Springs: MALOSSI yellow

1) I'm trying to choose the right main jet and rollers, so does anybody has the similar setup?

2) I used the short belt (PI856026) before but it breaks every 3000km. Can the engine get damage somehow at the moment when the belt breaks?

3) Do you have any recommendation how can I improve this setup for better performance?