It's definitely a boost in power that is easily felt. What made me notice it is being able to stomp on it at 35-40 mph and burn rubber with traction control ON (compared to like 15-25 stock). Also being able to chirp second gear is a good sign too. I can't really say much about it, because the day i took delivery of my car it wasn't licensed and i mashed it once, it was stock then. By the end of that night i had put on my 4" FWI, plugs, and TB spacer. And in another week i had the DP on, t-stat, and 3.4 setup. The 3.4 setup, when modded correctly with 0* KR, like my setup, is a night and day comparison to a stock vehicle.
Also , pizzi22 is correct. It will work, but i also made the switch to a tighter belt. If you want to use your stock one and don't want to fork over the cash, buy an oversized tensioner.