At a minimum you would need to remove the DSP amp (located down below where the CD changer is mounted) and replace it with the non-DSP amp. You would lose the rear sub that's in the back.
Mark from Tucson went from non-DSP to DSP (see
http://www.xoutpost.com/articles.php?...cle&artid=160), so going the opposite direction should in theory be possible.