E36 sound system....

[ViPER1313]

Just a heads up: speakers fail 1 of 2 ways - the cone and surround deteriorate and the speaker literally falls apart or the magnet burns out and it no longer works (or sounds horrible.) If the speakers are simply old and the surrounds and cone have deteriorated many places will replace both for a nominal fee ($30 to $50 a speaker.) Usually the magnet determines how "good" a speaker sounds so the replacement will simply restore the speakers to their original state. If the speakers sound good and are a weird size / hard to find (as seems to be the case here) this might be a viable option for you to consider.