I've definitely noticed a quicker pickup and throttle response. Sound wise, not much different... but I also have a flow master muffler on. The real test will be next week when we make a 10 hour drive for vacation. I'm curious to see what the MPG will end up being at.
My honest opinion: If I had to do it again, I probably wouldn't and would stick with the K&N drop-in and carbon filter delete. There is definitely a difference I can feel with driving, but the cost compared to the difference it makes doesn't seem worth it to me. That being said, it is a nice little piece of eye candy whenever I open the hood.
Also, I did see a couple of reports on taking off the grill shutters to get some better flow. I may try that before I completely say it's not worth it.