Its simple for DD you do not need an STI - it is purely a want. If you can afford it do it. No doubt it is a better enthusiast car to start from.
In May 2003 I wanted a wagon and there was no STI wagon, so I got a WRX. I knew I was modding over time so it was fine to enjoy the car stock under warranty and slowly upgrade to where I wanted it.
If there was an STI wagon at the time - I would have likely got it and done the same thing - the extra cost over a 5 year loan would have been just fine.