Just purchased a pair of Heresy speakers 1983, birch unfinished. Not here yet, but, I heard somewhere that it might be a good idea to update the crossovers. Also, I saw a pair that had mdf 3/4 " thick replaced the back panels. I didnt get to hear them. Any one have input on these mods? How much are new crossovers? I obviously will listen to them before I make any changes. I'm new here and just to fill you in, I listen to vinyl rnr, jazz, occasional classical. My source is thorens td 150 and 145 through a marantz 2235 and a marantz 2275. Just got back into audio and really having alot of fun. Thanks for any input.