I put this on my 02 Viggen a few months ago and like everyone else, the intake sounds great. I have not notice any increase in my gas economy but I guess that is because I'm too busy listening to the great sound coming from under my hood.
A friend of mine tried to accomplish the same effects with his factory air filter box by drilling some holes in it to increase the air flow; however he has not been able to create the same sound as the open air intake makes when the turbo spools up and then blow off the pressure. So I have to say this is a very nice engine upgrade for $130 dollars if you are looking to give your Viggen a more aggressive sound.
On a down side, my wife hates the sound so she does not like to ride with me too much. So I get more time alone to really wind up my Viggen and drive it like it should be driven. So maybe that isn't too much of a down side!

Rating: [5 of 5 Stars!]