Just got done replacing my zzp catback's 12" 320 stainless Magnaflow resonator with a 36" 409 stainless Magnaflow resonator I bought off SummitRacing for $100 shipped to my door. Drone has been eliminated, and deceleration is completely silent. I'm very pleased with the results, and my car is stealthy once again.
http://www.summitracing.com/parts/MPE-12641/
http://www.summitracing.com/parts/MPE-12641/