Man, there are some people out there who have the money to build a ridiculous car every year, like some guys around me. Then, they get tired of it and sell it to someone who's parents are writing the check for them (more often than not).
One guy down here (Dave Chu) had a WRX, maybe $30k worth of additional mods, had it *maybe* 2 years, just sold it, has put probably $15k into his new S13, etc... Actually, his is the white WRX displayed on
http://www.takaragarage.com, it got parted out long ago though.
I dunno, depending on what's in it, and how many miles are on the chassis/engine, $21k for a really highly modified S14 ain't bad, if I had cash (good luck getting a loan for 3x KBB). If you have done a swap, you CAN get more $$$ when you sell your car.