if you want the most out of the components, I'd install each set in a different vehicle....
there is lots of interesting shit you could do with multiple speakers.... and so far gumby has the best advice IMO..... but common, one mid is hard enough to find space for in a kick let alone two..... not to mention that a so called imaging tweeter probably should not be playing the same frequencies as your main tweet... IMO anyway....
if you want loud install both sets...... probably be more then you need anyway.....
otherwise Id keep it simple, stupid.......