Yes, went stage 1 on Thursday. NGP Racing didn't have the intake in stock, so they shipped it to me for free. Didn't get a CEL, and I'm not too worried about anything further down the road; like anything else, good sense and proper maintenance will hopefully suffice
I like the sound...I don't feel like I'm obnoxious leaving my townhouse neighborhood, but it's a nice deep rumble, and you can really hear the turbo spooling.
Regarding power increase: as others have noted, there's an immediate difference in throttle response. The car feels quicker as a result, even if it's just that reduced lag. I'm probably crazy, but I feel like I'm noticing the difference between having this and not more than I noticed the tune.
I didn't work today, but have my normal 38 miles of open highway commute tomorrow, so I'll update with further impressions and mileage (though I'm a little lead-footed right now, as I'm sure you understand)