I purchased a 2017 gt automatic with a3.15 rear dif. The exhaust did not have a deep enough tone for me or enough volume. After spending a great deal of time listening to sound clips and talking to friends, I decided on Magnaflow since I had that on my 2012 and was very pleased with the deep tone.
I wanted to leave my stock resonators in place and install an axle back. I found out that Magnaflow is no longer making the street version.

I sent Magnaflow several e-mails asking for info with no response. I finally called and was told that they were not going to make the axle back in the street version. I asked if I purchased the street cat back and used those mufflers but not the X pipe if that would work. they told me that they would not fit. Since I am so fond of the Magnaflow tone, I purchased the competition axle back and left the oem resonators in place.

That was a huge mistake, the drone is so bad you cannot stand it. If you leave the transmission in sport and shift if manually so you can keep the revs up it is not too bad. Any thing from 1600 to 2200 make your ears ring for hours. So my message is if you have a new mustang with an automatic and a 3.15 dif, do not purchase magnaflow competition axle backs.

 

You could get a set of 3.55 gears and move your cruising RPM up a few hundred to get out of the "drone zone". You'd probably have to get a hand held tuner to re-calibrate your speedometer.

 

Most aftermarket exhaust give you a drone especially 2000-2500 RPM. Mine actually has a full stock exhaust with the mufflers cut out, its pretty loud but I only have drone in 6th gear. Soon ill be doing a resonator delete and getting an H pipe.

 

Saludos, I went thru the same experience with flowmaster american thunder axle back. The drone was present all the time and I tell you, installed on tuesday and removed and sold on the same week friday. I may recommend ford racing by borla touring axle back ,you get the low rumble and comes alive when spirited acceleration but quiet at crussing speed,no drone at all.

 

+1! I have the Borla Touring Catback which has a significantly smaller resonator than stock. The rumble at idle is awesome. Hard acceleration is an attention-getter, but definitely not objectionable. 😎

 

Agreed a 100%, Borla is an excellent manufacturer. I added their resonator at the time when the long tube headers were installed on my car. My car is a little louder nowadays after the installation of the roush supercharger but still very quiet at cruise speed.

 

I Best AB out there for the money. I love mine no drone and get louder as they age.