Best passive X over point for mid/hi drivers?

OK. So i got currently a 2 way active front stage in my car. I'm running into midbass speaker problems past 1k, so I decided to lower the x over point. Thinking of doing active 48dB/oct for hipass and lopass in the MiniDSP.

LOW OUT: 80Hz - - - 600Hz
HIGH OUT: 600Hz - - - 20K



I want to put Morel CAM 558 2" dome midranges in my A pillars along with the Neo3 PDR tweeters.. need to run these together passive. Sensitivity is very similar between the two.
active Hipass for the mid starting at 600Hz or so at 48dB/oct

DIY crossover point/design ideas?


EDIT:

Morel dome mid http://www.parts-express.com/pe/psho...number=287-025

and
BG Neo3 PDR-W http://www.parts-express.com/pe/show...number=264-735

Thinking 4500k xover at 12dB/oct