bozak crossover upgrade

I have a pair of bozak concert grand's and would like to upgrade the crossover's,what componet's should I upgrade? and what are the values should I use,i listen to acoustic jazz and smooth jazz,i have read that there is a tobin upgrade for it but is it for the concert grand? I will be using tube amp's but may use my ss amp's,because I understand that the concert grands are power hungry,i would like to open up the midrange and high's, I also have a pair of symphony's that I would like to do the same thing too,also do's anyone know how to get to Mr Tobin-email? thank you