i worked at a lincoln dealership and i noticed that the low end THX sound systems didnt have that thump, the MKZ had by far the most bass in their system

the ones with the dvd player seemed to have better thump, but my biggest complaint is the MKS there is no bass in that

but back onto the subject, i would try to find out the difference in the amps and if at all possible just swap one out

even know your gunna be payin through the ***