In the huge peak-downforce days, F1 cars generated something like 1,700kg of downforce at around 280kph and weighed 605kg minimum. That's 2.8kg of downforce for every 1kg of weight at speeds rarely attained by any car. Equivalent downforce for a 1,500kg car, which is
very light by modern standards, would be over 4,200kg. To create anywhere near that much downforce at usable speeds would necessitate an aero package that makes even this...
...look tame; the wings would be ginormous. To overcome the drag created by those monsters would require an engine with at least 1,500bhp (assuming a frontal area of 2m^2 and a CdA of 1.1, both only generalized guesses on my part that are likely conservative).
It's just unreasonable by any measure.