Where are you based ? (i'm in NL).
I have some of these, i think it's better to change them as a pair as there seem to be different models around and the amp has to be adjusted accordingly (but at least with 2 the L and R will be the same).
You're sure the woofer is broken ?, it is powered by it's own amp (avant has 2x 2 poweramps, 1 for every speaker).