i think the 1x sound fantastic with the mod 460s, but I prefer the sound of the JW mod over the stock boddies
i've got a recent WSP show I ran ck1x/mk46 > aerco mp-2 > 722 just haven't tracked it out yet but it sounds great.
i think you will notice more of a difference in the mids/highs with the mod than the lowend, but Jim claims that the lowend is extended much lower after the mod, but I think its kinda moot since the Freq response of the caps will still be the limiting factor