I have a kouki convert, I’m sure you have seen it before when I ran over to SG (red Super Advans on it). It had half the km’s of most kouki’s selling, more mods, and was a few grand cheaper. Still by no means anywhere near as cheap as an S13 to build. To the OP, be prepared to drop the cashola., that’s all I am saying. 7-8K for a kouki is the going price these days. Then you gotta 5 lug the slat, put on some man brakes, and by man brakes I mean some real rotors and pads. That’s like what, 1500-2000K in parts there + more for labour. Then you’re gonna have to run decent rims and rubber which is another 1500-2000k. Then if you want someone to swap an engine in you are looking at 5K basic. Another 2K for a front mount installed roughly, expect to drop 4-80" on a catback, 200 on a good boost gauge.
DO NOT expect to pay less than 15g’s to play unless you buy a good base car like mine for example (which I will lose quite a bit on most likely). I am just letting you know this, speaking from experience. Double your budget and I will put you in one of the cleanest S24’s in Ontario lol.