Instead of asking a question that has been asked numerous times. Use the search function, or hell even google it and you can read about it on NASICO.com, iwsti.com, and numerous other subaru specific forums. To me its garbage, someone took someone elses design and replicated it with inferior materials, and less R&D or even knowledge of the piece. But others seem to think that when you buy name brand you just are paying for just that, the company name.
"2007 WRX- PPG'd, 20G- Tim Bailey tuned
Stage 2 2005 WRX