True, people prefer FRCs, but you act like cages aren't available for the car to improve structural rigidity. Don't even say that the people on this forum wouldn't put a cage in it, I've see Auto S13s with cages.
Adjusted for inflation, that's around 20K, which does indeed fit the 25K requirement. But 1989 had much more slack safety regulations and emission regulations. Companies have to pay for the technology to meet emissions, which they pass on to the customer. So, don't even pretend like the car market is at all comparable to nearly 20 years ago.
Also, if you do find a RWD coupe for 15K, it's probably going to have <100 HP and the fit and finish worse than a GM product. Have fun modifying your brand new car and voiding your brand new warranty.