I won't ever sell this car, but yeah it would take $20K to break even.
If I were building this car with a Fiat drivetrain and more accurate parts, it would likely fetch $100K at an auction; there's two on eBay Italy at the moment for $160K+ and there was one on eBay US a few years ago that went for $120K, and the workmanship was awful . Here in the states, finding Fiat parts is a nightmare and the engine that came with the car was a sad 1.8 with a cracked block. There is the new 124 Abarth, but it has a tiny 1.4 Turbo, and the 500 comes with a 2.4 Chrysler engine which I wouldn't consider in a million years.
Here's a real rally car that sold for $385K
1980 Fiat 131 Abarth Rally for sale at RM Sotheby's London
rmsothebys.com
These cars are desirable because of how few there are in the US, and because they won the WRC 3 times back in the seventies.