Audio Upgrades

I recently purchased and took delivery of a 2016 GT350 with the Sync 3 head unit and the standard 4 speakers. Last week I took the car in to have the audio system upgraded by swapping the stock speakers with Focal K2 Power 165KRXS, adding an Alpine PDX-V9 Amp and a JL Audio Stealthbox. Driving away from the installer, I noticed engine noise emitting from the left and right channels as I accelerated. I do not remember the sound being present prior to the upgrades. The sound commences at between 3,000 and 4,000 RPMs and fades out above that level. I spoke with a representative from the Ford SVT team who guarantees me that the sound is not being generated by the head unit and is the result of poor installation. The installer is pointing at the head unit. Any and all help is appreciated.

thanks

As a follow-up to my earlier post. my installer dialed down the gain on the amp and the noise level is much lower. I have spoken with both the local Ford dealer as well as with the Special Vehicles Team and both believe that the noise is due to the wiring. One interesting note, my installer accidently hit the trunk button and the sound went away completely. This fact seems to completely contradict the guidance from Ford that the noise is a result of interference somewhere in the loop of the added components while the vehicle is under load. I think the issue could be some quality control at the Flat Rock plant with the wrong SYNC 3 systems being put in the vehicles. Ford uses the SYNC 3 to introduce engine noise into the interior of the vehicle in other Mustang models. I have asked if there is a way to check the hardware/software of the unit and have not received a response.