Check your registration papers/documents, if the tire size is specified there (it should be), then
that's the tire size you need to have on your scoot to keep it road legal. At least here.
As for handling, I've ridden ONE 250cc scoot whose owner swapped the rear 14" wheel
going from 130 to 140 width. It made the scooter turn in a lot a lot slower (it basically
resisted direction changes a lot more then before).
Taller wheel will also change your gearing.
Those tires will also be more expensive.
There's a good reason manufacturer decided to use the tires that you
have on right now, and it's not one of those things that should be messed with.
But what the hell, try it if you must.
If you want more comfort, change the seat, not the tires.