I would say EV converted Porsche 944, or RX-7 with an Insight engine swap, but I'm guessing you're not looking for your own Project Car Hell.
I think the MX5 is the best bet. However, of the Fiero, Mustang, Celica, and Miata, none of them meet your stock FE criterion. The Fiero does well in highway FE (old rating:35), so maybe it would do well around town with P&G.
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