I have Helix turboback and uppipe on my 05 and its a nice, deep rumble, but then again, all WRXs with exhausts have a deep rumble. There are exhausts louder then Helix, but I think it has a nice sound.
i just ordered the invidia dp ( getting it tomorrow according to ups). I have 3" catback and it sounds mean, as you guys know. What kind of change in the sound can i expect? I heard that it may sound deeper.
Also, what kind of hp gains can i expect? Invidia claims at least 20 hp.