2 whp less at peak, and 6 whp less in the mid range. car ran richer by 0.3 (11.2 stock Vs 10.9 K&N)
I dynod the viper 3 times, got same power # (531 and 530), installed the filter while on the dyno, took 3 min, the car cooled down more then it did between the first runs, ran it again 2 more times, got the 2 whp lower and 6-8 whp in the mid range (528s).
The car ran richer, so it will have to lose power on an NA engine i guess.
I did leave it on.... will drive the car around some and try again. as i did not give the ECU any time to re-learn, not even sure if it will make a difference. We will see..