anyway here is my story diffirent than yrs, i have listened to music in new shape and 02 civics and it didnt rattle at nominal listening,
so i suggest first try stuffing some foam where the rattle is. speakers are mounted on meatal base underneath the panel not on panel. and company has tested the music system before car is sold so under exterme listening level there might be rattle not at nominal,,
i ve known here ppl fixing 12" woofers in car trunk and that sounds horrible with whole trunk shaking