I swapped out a fairly middle of the road Sony set for the Empeg and a 700W MacAudio amp but kept my standard Subaru Impreza speakers. At LAME VBR level 7 (2nd from worst quality) it is distinctly better than the CD player in terms of noise floor and crispness. I have some tracks at 320kbs fixed (due to a mistake in my ripping settings:) and they are very big files but without any discernible quality improvements over my small VBR files. Of course the sound environment in the Impreza isn't ideal for audio so if I ever get something other than an Impreza (doubt it) then I may need to re-rip at higher quality.
It is just so good/fast/easy!