My 2 cents opinions are:
Dont ''upgrade'' the original xover, unless it is broken.
FullRangeMan -- You're posting on the GR Research circle and encouraging a new member not to take advantage of a crossover upgrade GR Research provides. That ain't cool.
Hey JR -- disregard that advice and upgrade your speakers ASAP! You'll glue and zip-tie the crossover parts onto some thin wood, MDF, or pegboard. Another option is to ask GR Research to assemble the crossover for you or recommend someone who can. For what it's worth -- based on the pic in reply #68, the new crossover board appears to be twice the size of the stock board.