MPG wise, will vary based on how you use/abuse it, how much you weigh, if you have lots of wind and hills.
That said... I got around 75MPG on my stock stella. (225lbs, some hills and wind, me pushing it pretty hard.) When I upjetted/deblued/sito+'d it, while it ran, I was getting 65MPG (give or take a few). The extra power and top end was nice for me, well, until it died.
In comparison, I have a stock (24/24) P200e now, and it gets 55MPG same rider, conditions.