I will have to look for the thread or video on YouTube. Someone did the 11378 in place of the resonator which then they were able to do the mtech bumper to have to true duel exhaust like the 335i. This is what made me pick the Magnaflow exhaust, I saw his video and wanted to be able to do the duel exhaust later.
I will see what I can find for you. his sounded great. So I figured with our headers it would be alittle louder.
Here is the video I went off when i was looking at Magnaflow Exhaust and Duel Exhaust for our car. He did 2.5 single in and 2.5 duel out. They also make a 2.5 duel in / 2.5 duel out which i also looked at.
New - 2013 - 320i - 15% Tint - Future Mods ( BMS Tune, Suspension, Wheels, Exhaust)
Sold - 2007 328i (3-Stage Manifold - BMW Perf Intake w/Scoops - Powerbox - Magnaflow Exhaust - MMW Headers - KW Street Comfort - VMR 701s 19' w/M3 offset - BMW Strut Brace - 330I Brake Conversation - 5% Tint All Around - 8K HID Fog Lights -Angel Eyes)