A metro Xfi can run at 15mph in 5th gear
the Xfi cam and advanced timing lower the power curve significantly. (peak around 2K I think) A cam would be a good investment, as well as a 4-2-1(I think that's right) exhaust header to lower the power band but since you're looking to keep it stock...Can you advance the timing on this car, that should lower the power curve some and give better torque in the low end.