I installed this on a 2000 9-3. My stock valve was pretty much fine, I just wanted to future-proof the car (and the nifty whoosh noise doesn't hurt).

With my open-air intake, the psshht! sound is slightly more pronounced than with the stock valve; it's enough that you can hear it outside the car, but not obnoxious or ricer-y.

Installation is very easy; even easier if you have a couple pairs of locking pliers - maybe ten minutes from beginning to end.

This comes with all the springs and washers you'll need to upgrade the holding power of the valve as you upgrade the car, and it looks to be a very solidly-made unit - I expect that it will outlast most of the rest of the car.

All in all, a very nice piece of equipment.

Rating: [5 of 5 Stars!]