Good to hear you did decouple. The way they are made you did the best thing you could to actually make a music sub. REL is old tech with great paint. I've fixed quite a few VMPS and REL subs for music.. Boom Boom is easy. Audiophile is a little tougher.. I secure a butt plate and add, springs, pods or air ride. I've used all with great success. Air bags decouple the most complete, they can be a PITA if not thought out.. I used a 10 and 15" bicycle tire tube under 2 400lb columns. worked perfect for 15 years.. You could tell when they needed air. Once a year two pumps each.
Nobound with ear plugs stuffed in the springs does ok.... :-) Get the black ones, they don't stand out like a sore thumb..
I'm only in to ugly women, my gear has to look really good. Easier maintenance for both to tell the truth. :-)
Regards