How can I improve my music systen on a Suzuki XL-7 on a budget of
180.00, at presentI have a Clarion Stereo/CD (I dont want to change)
and 4, 6.5 speakers allso Clarion.

Free advice.. see if it jives with what else you hear...
A cheap amplified subwoofer (like a bazzoka tube for your trunk (but a
cheaper brand)), and bass blockers (little components a few dollars
each that plug in right before your speakers) will make the biggest
difference. BLock the taxing lows from your regular speakers plus add
a healthy amount of thump (but not ridiculous amounts). Should
definitely be within price range assuming you do it yourself.

Hi perdido-ga,

   It really depends on what you feel is wrong with your existing music
system, and what you wish to be improved.  If your speakers sound bad,
you need to identify, if it is due to distortion in the amp, or due to
speaker resonance. If it is the distortion of the amp, you could replace
your current amp, with one having very low THD and NLD. If you find resonance
(over sounding at particular frequencies only), you probably need a crossover
network, and additional matched speakers. If the sound is good with a different
or better speakers, your speakers might need replacement.  Also there is
a possibility that you are having too much vibration due to running engine,
resulting in increasing the volume, distorting the output produced. In that
case, the easy way is to buy a noise cancelling headphones, disassemble it
to seperate the two noise sensing microphones, extend them and glue it to
the places that produce most vibration(or where you want the noise to be
minimized), feed back the output of the speakers back through your music
system(or connect two seperate speakers hidden invisibly and driven by an
additional amplifier).  You could also make physical modifications, such
as attaching sound absorbing pads under hood,carpet and on the walls.  It is
more work, and may not be very effective, and could make selling your suv
difficult(since the changes were not oem).

Regards
ldavinci-ga