1) The heavier the driver and/or passenger, the slower it is. How much slower depends on the weight of the person or persons and how they drive; IMO. It would be interesting to see if it affects it and how much.
2) Here is the
Lojack website.
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3) The Fortwo might be sporty to some (especially the cabrio) but I doubt any one would consider it a sports car.

I think accerlating too fast can waste gas; IMO.