I just installed this on my wrx 2 hours ago and have been driving around since.
The install was very easy - no seized bolts since my car only has 58xx miles and has not seen winter yet.
My engine is completely stock other than this muffler.
I cannot tell if there is any change in performance yet... The volume of the exhaust certainly encourages lots of WOT driving and makes it easier to match revs smoother, and perhaps there is the perception that the turbo's spooling up faster although this could be because the sound makes you 1. downshift 2. step-on-it 3. get excited.
The sound: I wanted a muffler to get some aural effect in my driving experience.
Inside with windows closed: very very quiet. Just a hum. The exhaust tends to hum at medium volume and as you open up the throttle to WOT the hum becomes a faster "strumming" sound (hence stromung!). It's quite nice (would've been a great OEM exhaust). I thought at the higher revs it would get real throaty and raspy like my old Alfa Romeo but this one is a gentleman's sound - very subdued.
Outside: The stromung sounds great at idle, nice duba duba duba duba sound. dubax2 when someone blips it
Windows down driving is very enjoyable
I am happy with this exhaust
Would like to hear some other wilder sounding exhausts too, but this is definitely very liveable.