Apologies for the late response!
Battery:
The battery supplied by the retrospective scooter is: 18s 64v 26ah
Calculations serve that this is a 1664 Wh pack.
18s and 10p configuartino of the cells.
This breaks down to be 180 individual Lithium-ion cells.
Now, I have seen these cells on various websites for around 1 to 2 dollars per cell if you buy them in bulk. Bulk in this case is around 1000 or more cells.
Throw in a $50 battery management system and some decent soldering skills and you've got yourself an additional battery pack for around $250. Not bad! Especially since you could double the cells and get closer to 60 miles of range and be in the ~$400 range.
I have attached a pic of the kit as received from retrospective so you guys can get an idea of the size and shape of everything.
Here's something else to think about. As I was working on this kit., I read some of the parts #s and I realized that a lot of this stuff can be bought individually online. Mostly from China. Thanks also for the old p200 conversion post from last year that was linked!
I received a quote from QS motors for a 10-inch hub motor and controller for around $800.
So, I reckon with about $2k and some fabrication skills, you can definitely make this kit yourself.
So, at the end of the day, the retrospective kit has a convenient cost. But with that added cost comes customer service AND a guarantee that it will work and fit. For the less mechanically/DIY-minded, that is definitely worth it.
I've got a pretty rough p200 sitting around and I might try to make a kit for it myself. I'll try to stick to a $2k budget to see if this is truly accessible for the average garage mechanic like myself (with a garage mechanic budget!).
Finally, the owner of Tiffany the electric Vespa just sent me a pic of it on its way to be inspected by CHP and the DMV. I'll let you all know if it passes and if it is awarded the coveted "EV" title here in CA. Worst-case scenario if it fails, I'll help him put back in the old engine and just register it as stock...