sti stock vs evo stock, go with sti. its faster and handles better stock.
tunability is yet to be determined for really either cars cept for what ^ said
personally i love the evo look, but i would go with the sti be cause of the sound and boxer engine.

its all about your preferences, dont let us make up "your" mind.
give them both a few test drives, take your time to decide. cant go wrong.