I have to second the "Toyobaru twins". I'm a V8 American car type, but if I were in the market for a $30k sporting car with great fuel economy, the FR-S or BRZ would be at the top of my list. Only downside I can see about this car is it only has 2 seats. Otherwise, it appears to be a great all around sports car.
Another option to think about if open to less economy and more performance is the 2016 or newer Camaro. The Camaro SS1 performance/ $ value cannot be touched. 460hp in a balanced chassis, and can still knock down avg mpgs of low 20's. Styling I would imagine might be the biggest hangup for some...you either love it or hate it, but there is no denying it as a great car. That one is the next car in my crosshairs down the road. If your not in a hurry and open to the Camaro, my advice would be to look for a used '16. I have seen 1 year used Camaro SS' for low-mid $30k range.
Good luck to you.