Hi, we have a 2006 Mustang Convertible GT with Shaker 500 unit the ID number is 6R3T-18C815-HD does anyone know what other Shaker 500 units will be compatible? I founded one that has ID number 4R3T-18C815-HJ any help would be greatly appreciated

Thanks

 

Any 05-09 will fit. I just sold one for $50.00, from my '08, with a broken
CD changer...

A Shaker 1000 will also work, won't change the output of the head unit.
Won't be utilizing the 2nd subwoofer output in J4 either, but it will work.