Just purchased this sub, and based on the recommendations of poster's on this forum and others about modifying the SA-WM40 model, I tried to do the polyfill mod. The speaker on this sub is countersunk into the face and after undoing the eight screws there was no indication of outward movement of the speaker! Has anyone else modified this particular model? Could it be possible the speaker is glued as well?? Or is it just a tight fit??? My dreams were to purchase an SVS, HSU or even an DIY sub, but this cam up for $150 Cdn., thus couldn't pass it up! Otherwise, stalk it sounds good, maybe a bit "boomy"(which supposedly the fill will fix!), have to have the volume on the sub turned up 2/3 and the sub setting to +7 - 10, but what can one expect with 150 amps! Thanks for any advice!