For the Vespa GTS is finally also a rear hight reducer kit available. For the Vespa Primavera / Sprint there is already a little longer.
For the Vespa GTS, the height reducer kit should bring about 2cm reduction (0,78 inch) in seat height, so that rider comes better with the feet on the ground.
Attention: only in compatible with series shock absorbers and series exhaust.
Vespa GTS rear hight reducer kit:
https://www.sip-scootershop.com/en/product/height-reducer-kit-rear_MV3025003
Vespa Primavera/Sprint (only 125/150):
https://www.sip-scootershop.com/en/product/height-reducer-kit-sip-rear_MV667872
(one of multiple available products)