You won't get but 2-3 hp out of it which isn't really noticeable. If you have an auto you will notice a better 1st to 2nd shift. The new noise it makes is cool and addicting so your mpg might go down.
Adding an intake and exhaust won't really give you any more power, but the sound is nice so don't stress over having to wait for an exhaust. A bigger exhaust will help a turbo spool up faster so you can get to the power faster, though, so it only helps with a turbo PT.