Wow, I know exactly where you are coming from as I was just in the same situation. How much do I spend? Where do I stop? I originally was looking for a 09-10 STI. Figured the car had done the worst of its depreciating and I got the full blown race spec.

To be truthful what I found was they don't depreciate 14% each year for the first 2 years like most cars and the extras were just over kill. Really depends on if u want / need from your car. a daily, a sunday driver or a project?

By the time crunched the numbers and all the crap I settled on a 13 WRX S Edition.
Had all the fruit, no previous owners and a good drive away price, compared to a second hander. Basically the same performance and output as an STI but without the go-cart suspension. But hey each to their own. I wanted a daily for winter and I am not a huge fan of mods or screwing round with cars.