the one in the newer IS models is not actually a levinson developed stereo as in the LS, GS, SC, RX but instead is one that they claim to have put together using the parts they developed from those stereos
i'm not complaining in any way about the quality of the sound, i think its brilliant (hence i have no plans at all about changing headunit, amp, speakers, etc.)
however, there is definitely not enough bass in the system and i'm just trying to find a way to enhance that (especially considering that the older systems had this, which were in fact nakamichi compared to the fujitsu units in the newer cars)