Audio Systems: RFI FEEDBACK, factory speakers, rf noise

Question
I HAVE A 2003 HUMMER..I JUST HAD A KENWOOD DOUBLE DIN 7" DVD INSTALLED IN THE DASH AND TWO DIRECTED 7" MONITORS INSTALLED IN THE REAR W/ AN ADDITIONAL DVD PLAYER UNDER THE REAR SEAT.( PROFESSIONALLLY INSTALLED)  .I KEEP GETTING ENGINE RFI...THE INSTALLERS PUT A LINE MODULE ON IT AND IT CURED THE NOISE, BUT MY VOLUME WENT DOWN TO NOTHING..THEY MESSED WITH IT FOR TWO DAYS AND STATED I WOULD HAVE TO CHANGE MY BOSE FACTORY SPEAKERS BECAUSE THE AMPS IN THE SPEAKERS ARE CAUSING THE PROBLEM..DOES THIS SOUND CORRECT OR IS IT JUST A GROUND PROBLEM THEY CANT FIX? THANKS IN DAVANCE.  

Answer
Typically if done correctly interfacing with a bose factory systems should work ok to say the least.  The installed the filter and basically just attenuated the RF noise out but also the regular sound as well.  I would say to find a better shop in your area and let them go over it as well as a second opinion.  Replacing your Bose systems shouldn't have to be the absolute answer.