The Head Unit Will not make the bass. For Bass you need a AMP & SUBS!! As far as interior speakers go stick with round speakers. 5 1/2 or bigger! Oval shaped Speakers don't give that good of Sound reproduction.
The only difference you will see from deck to deck is overall Sound Quality from the Hi end Co. Sony, Pioneer, Kenwood, Panasonic, JVC, Awia, etc. all sound the same. Take any of those and SWAOP it with a Clarion , Alpine, or Eclipse and I bet you anything that you will here a dramatic sound quality improvement!!!!
Those Bass enhancers are only adjustments to change for different kinds of music and to help customize your system. They are not going to make or Break you! If you want Bass there is no way around the AMP&SUB!!
95' Cavalier. Clarion 7575, Clarion 560 EQ, RF 800.2, RF400.2, Aura 6 1/2 Comp, Aura 6 1/2 Coaxials, 2 12" Kicker SoloBarics