Video by Vespa Motorsport via YouTube
Source
SnapOn 10mm Socket Part # STMUM10A
8474115 Exhaust Assembly: https://www.scooterwest.com/oem-usa-exhaust-muffler-assembly-carbureted-et4-lx-lxv-s-125-150cc-828540-831870-831869-8318705-8442905-8454715-847411.html
8474115-BK Exhaust w/ Black Shield: https://oem-usa-exhaust-muffler-assembly-carbureted-et4-lx-lxv-s-125-150cc-828540-831870-831869-8318705-8442905-8454715-847413.html
B0173915 Exhaust for Fuel Injected Models: https://www.scooterwest.com/oem-usa-exhaust-muffler-assembly-injector-lx-lxv-s-125-150cc-for-carb-see-8474115.html
434716 copper gasket: https://www.scooterwest.com/vespa-et4-lx-150-exhaust-gasket-packing-434716.html
436947 copper nut: https://www.scooterwest.com/brass-exhaust-nut-each-436947.html
478761-SH upper bolt: https://www.scooterwest.com/bolt-exhaust-muffler-upper-bracket-50mm-vespa-et4-lx-150-478761-sh.html
478761 lower bolt: https://www.scooterwest.com/bolt-exhaust-muffler-for-lower-bracket-60mm-vespa-et4-lx-150-478761.html