FWIW, all the e46 non-Ms are 10K cars. Meaning if you bought it at 5K, you're likely going to spend another 5K over the course of your ownership for it to be a great (refreshed) car.
That said, it also depends on how picky you are with maintenance. For me, I'm very picky and everything needs to be done. So my e46 is more than a 10K car now, but at least I have the peace of mind to be able to take it on a track or road trip.
Good buy - I think. All VA WRX STI that I've seen are in the high 30s to 40s range. Here's one
2016 Subaru WRX STI Sport Tech - $34,000 - 52,500 km