The 2.5 flat four turbocharged engine with 305 horsepower is carried over, while tweaks in suspension will improve handling. The 2011 model year STI has stiffer spring, bigger anti roll bar, and new pillow ball bushings on the front lower arms. Also, US dealers are now requiring synthetic oil for 2011 models. It will now do 0-60 mph in 5 seconds and the quarter mile 13.7 seconds



Above from Wiki, the main point is the engine = a carry over. Here's the point.

The engine block is aluminum and not sleeved. The Deck is open meaning it'll lift at best and pop at worst. These motors from my experience (I hand out almost exclusively at a Subaru tuning shop Precision Tuning and so on) pop quite easily and do not handle detonation. All I see them do is build motors. The issue is that if these things get any over boost, they let go. My Evo, I hit 30PSI on a cold night, whoops, lower it to 27. No issues. Why? Iron block, proper pistons and rods although the STI has great pistons, rods are suspect. The Evo head is a closed deck design so it holds. Just an iron brick that protects from a lot of stupidity.

I am of course extremely biased but a new Evo owner should get a 5 Speed Evo IX. I like the MR and have a lot of experience with these cars so I can handle the 6 speed properly. The Sti is a nice car but it doesn't come close to the Evo IX or even X for that matter. it's a shame really because the STI is a better daily driver, smoother, nicer cabin, but it costs a LOT to make them fast, that 2.0 Evo is simple, garish, and just keeps winning.

Link to the article... http://www.roadandtrack.com/tests/co...ts-sti-vs.-evo

Video... http://www.youtube.com/watch?v=jz2_24yTMLA