Well, 2 weeks ago I installed the K&N CAI on my 16 Tahoe and really am loving it so far. Install was a breeze and time wise it took about an hour. I have already noticed way better throttle response and as of yesterday an increase of 2 mpg average for my driving habits. After reading a lot of threads here I also decided to upgrade to a performance cat back system. I decided to go with the Corsa performance system. I have a local shop doing the install next Tuesday and getting exciting to feel and hear the performance difference. Corsa is also running a $75.00 dollar rebate so every little bit helps. From some of the videos I have watched the system sounds great.