If you are looking to tune it you should definitly go with a Vino. I have 2 Tomos mopeds and 2 scooters, a Vino and a Zuma. I have done the same things to all of them, 70cc kit, exhaust and bigger carbs. Out of all of them the Vino is much faster. The Zuma has poor gearing and is heavier. I ride each of them regularly and I like certain things about each of them.
If you are going based on price go with the Tomos but I would go overall with a Vino.
This is a really good site with parts for the Vino and the Zuma. http://www.provoscooter.com/shop/default.php
This is a good forum of scooters that I visit all the time, which has some good info. http://www.provoscooter.com/vbull/index.php