Custom Magnaflow exhaust on new iM
 

It's really not as loud as the video makes it seem, but here's the final product.

Under the car there are 3 mufflers. I had the first muffler (just aft of the last O2 sensor removed and replaced with a Magnaflow 24" long 6" round straight through muffler. I left the resonator just before the rear suspension, and the stock rear most black muffler.
I am very happy with the final product.

I also noticed on the inside of the stock air box there is a post filter at the top of the box that I removed when installing the TRD panel filter. The car is a ton more responsive, getting better mileage, and noticeably quicker when I get on it. Purrs like a kitten.