hi i have a pair of JBL L100S's which are the military px version of the t3's if i'm not mistaken. So anyways, i bought them back in 1990 and it would seem that people have their crossovers and tweeter diaphragm foams redone after a while. my question is can these 2 jobs be done somewhat easily and at what cost by me and how do i go about doing it? preferably, anyone know where i could get them done? also is there a way to tell if they really need updating? i don't have golden ears but they still seem fine to me. thanks