Problems with Infinity Prelude MTS mid-range

I have 6 prelude mts's, have had extensive problems with the subwoofer amplifiers (5 of the 6 have needed repairs) I've also "blown" two midranges over 6 years, spiders detached from voice coil, possibly from being under-powered, rather than over-powered. The dust caps seem poorly attached on several drivers (poor fit), but don't buzz or rattle (other than "blown units" that the partially delaminated spider allows voice coil to rub in gap)Certainly not built with the "care" one would expect in this price range...

I've had problems with the sub amps (have 6 prelude subs & 3 intermezzo subs,very similar amps) All but 2 have had the amps stop working, & one has hum issue. Repair shops have no incentive to repair, as reimbursement for warranty work is very low. I've rewired & using crown amps with a velodyne sms-1 to power/eq (also a few velodyne sc 1250's power amps)