@esarhaddon , fan of PVC foamed sheet stock here as well. One has to treat it with a certain amount of care, since it will dent and scratch....
But I doubt there's many that don't beat up their speakers on a regular basis, anyway. Years ago, JBL marketed a bookshelf speaker that was similar in size to the L100 that was our 'shop units' that performed beautifully even when set to 'out loud' a table saw in a large 2 story space (40x 100, more or less....never put a tape measure to it...).
Didn't cost mega$, either....but it wasn't available, then or now....