<span style="color:darkblue">If you honestly want opinions about which car is better, asking of Z and STi forums is not the way to go about it. You should go to general car forums and ask.
gen[M]ay is usually a good place for that.
As far as trims go, it all depends on what you want in terms of options. If you want leather, you are left with only the Touring. If you don't, the other trims start from the Base and make changes throughout. A lot of people say the Enthusiast is the best place to start, others say it's the Base. Some people want the Track for the Brembos and the navi. And in the middle of all the is the Performance. All of the trims come with the same engine, transmission, and suspension.
As far as modding goes, parts are still relatively expensive because the car is still new. Also, you won't notice too many gains unless you decide to go F/I (the STi already is).
As for insurance, well that varies greatly from state to state. Your relationship with your carrier can also affect your rate.
But honestly, drive the two cars. You're comparing a RWD sports car to an AWD sports sedan. Which one is better depends on what you're looking for from the car.</span>