You have to look at this comparison from different stand-points, if you are looking for tuning one them the evolution is your best bet. The reason for this is that u can handle up to 500 hp from the stock block because its cast iron. The subaru isnt the easyest thing to work on in this case because of domed pistons and the fact that it is a flat boxer engine. The 4G63 found in the evolution is much more proven its been in many cars withing the last 15 years therefore options for tuning and tuning advice is endless. If you are looking for a daily driver that you wont tune what so ever then most would pick the STi because it comes with more power right off. At the end you have to test both and see which you like better, and besides all the specs ur supposed to have fun in it so before anyone says ones better you should test them.