Trying to determine what happened to my car. 2013 WRX with 3500 miles. COBB catted downpipe,Invidia cat back, AEM intake and COBB stage 2+ flash. Mods installed in April and car ran fantastic through October. Then the car started backfiring, loosing power and having a uneven throttle response. I'm also blowing a lot of carbon out the tailpipes. I am getting a whine that almost sounds like drivetrain lash above 3500 RPM. My best guess was the stock BOV was blown so I have ordered a COBB piece to replace it. Took off the factory BOV and it seems fine but I haven't installed the new one yet. Before I completly pull my hair out and take the car to a speed shop for a diagnosis I was hoping for some help of if anyone has experienced this issue.