Those are some of the best subwoofers ever made. Take a look at BK Electronics, they are the factory direct OEM manufacturer out of U.K. who made the REL ST (Strata, Storm, Stadium, etc.) line. BK makes the best subs in the world, IMO. XLS400 would be a great replacement for the Storm III. Monolith Plus is out of this world amazing.
My recommendation is sell the Storms for parts and buy BKs. Or do a full electrolytic capacitor recap on each Storm’s amp. Electrolytic capacitors are 99.99% responsible for failures/issues in these amplifiers. Caps are easy to replace, buy good brand such as Nichicon from DigiKey, Newark, Mouser.
My recommendation is sell the Storms for parts and buy BKs. Or do a full electrolytic capacitor recap on each Storm’s amp. Electrolytic capacitors are 99.99% responsible for failures/issues in these amplifiers. Caps are easy to replace, buy good brand such as Nichicon from DigiKey, Newark, Mouser.