Dont listen to these people that have never driven either
Ive driven both and worked on both.
EVO hands down
Have you ever priced out performance parts for a STI? Modding a STI is SUBSTANTIALLY more costly then a Evo, as are the repair bills
Also the evo has a less flakey AWD system that i feel is more reliable / better, not to mention it handles alot better stock for stock, but just from a modding standpoint, the STI is costly compared to EVO, that alone would get me a Evo over the STI, along with the other points