That 90 looks like a good shout. If all they have done is stick the kit on there (and changed the studs/exhaust/gearing then it'll be hoot.
Agree on the seat and mudguard though.
That LX15o has no keys, and as they have a transponder key setup it's big expense to get a new lockset, recode the immobiliser, etc, as well as recommissioning it. Not worth it.
Vespa throttles never used to have return springs - the lack of one allows you to indicate right without slowing down. They relied on the carb spring, which isn't that strong on a DellOrto SHB. You won't fail an MoT because of it if it was never there in the first place.