Unless you have measuring equipment and/or are an experienced speaker designer, I don't think you'd end up with very satisfying results from cannibalizing the Axiom drivers.

I'd either sell the VP150 or try to re-purpose it - either as a center in another system or a rear in a 6.1 system. Or, if - as you suggest - the VP150 value is low right now, BUY ANOTHER ONE and use them as mains in another system.

bibere usque ad hilaritatem