I've noticed the 06 TSX is a good factory sound system; but, it is +15 year old technology. The ELS sound system is a step up; but, that is also around the same age. The big advantage with the ELS is really shines with DVD-A. You will think you have a totally different system once you put DVD-A into the ELS. Sounds about the same for both systems with the nod going to ELS with FM, XM, CD, or AUX input.
Son - 06 TSX 5AT w/ Navi, Carbon Gray w/ Quartz
08 RDX Tech, Moroccan Red Pearl w/ Taupe
11 MDX Adv/Ent, Palladium Metallic w/ Ebony
19 MDX sh-sh-awd Adv Fathom Blue Pearl w/ Graystone