Crossovers are tuned to the cabinet; its volume, and the shape of its front baffle. If you're putting Axiom's drivers in a custom cabinet, the M2 crossover probably isn't ideal.

Building speakers isn't hard; building good sounding speakers is. I say hold on to the intact VP150, and sell it, trade it, use it some other time in the future.

Pioneer PDP-5020FD, Marantz SR6011
Axiom M5HP, VP160HP, QS8
Sony PS4, surround backs