Compared to modern audio system technology, Bose is junk. But if you
want to replace it with a high end system with external amps, you have
to be willing to install all new speaker cables in addition to what
ever wiring is required to support your aftermarket head unit,
amplifier, subwoofers etc. and possibly a bigger alternator (if you
intend to go with big amps). If you are going to use subs, it's hard
to find a subwoofer case for dual 12" subs that will fit between the
wheel wells; it would be better to use dual 10" subs. I did all of the
above on my 1990 and have 30+ hours of time invested and I'm still not
done yet. Also you can sell the Bose junk to any number of outlets for
$200-300+ which will help offset the cost of your new system.

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There is a adaptor out to allow you to keep the bose spkrs and replace the
bose radio with a aftermarket unit