Just installed the Kn filter set up. It seems that the acceleration has improved slightly. The noise sounds similar to the old four barrels kicking in. It definitely resonates into the cabin. My truck has a magnaflow muffler so it's a little loud but nice. The instructions were pretty clear and installation took a little over an hour. The system mounts solidly. I would've preferred metric bolts for installation just so everything is uniform. I would rate it 4 stars across the board.
Value for the money
Autoanything shipped very quick and arrived as ordered. The K&N 77 Series system drops right in without any issues. The instruction sheet is a bit vague at points, but if you are moderately skilled in mechaical abilities, you should have no problems. Too early to see if I gained in MPG, but the extra power is clearly evident at 3500-4000 RPM. Sounds really good too. Nice product.