I just bought my WRX 2 days ago. The dealership mentioned there was a leak in or near the resonator, no biggie... Been there before. I got under the car today and noticed the bolts connecting the muffler to the rest of the exhaust pipe broke, leaving the muffler hanging by itself. So that means the best bet it just to replace everything behind the downpipe/headers. I found a Spec-D Full Catback (wrong muffler, and exhaust tips for my taste) for a WRX for roughly $130 (USD). The site like many others doesn't specify whether it's for the EJ20T, or the EJ25. Should it work, or be safe on the EJ20T?
The full name of the kit is "SPEC-D Tuning MFCAT3-WRX01 Subaru Impreza WRX Sedan Wagon Turbo Full Catback Exhaust System" on Amazon.