is it possible to add a sub to the factory head unit and still keep the sync?

[nugxnxhash]

i have a 08 ford fusion sel with sync, i wanna hook up a subwoofer in the trunk but want to keep the factory head unit and keep the sync also. is this possible? please help me!!!!

[swatem]

i have a 08 ford fusion sel with sync, i wanna hook up a subwoofer in the trunk but want to keep the factory head unit and keep the sync also. is this possible? please help me!!!!

 

I just found this on another forum. I am going to give this a try in the next few weeks. This is their website but I found it cheaper by doing a google search. I had installed an amp using a line converter tapped into the rear door speakers but it affected the sound quality to much. Hopefully this will work alot better because I'm pretty satisfied with the stock radio unit.

 

http://www.pac-audio.com/productDetails.aspx?ProductId=548&CategoryID=28