as far as the crossover placement i found a perfect hole under the passenger side dash where it sits perfectly just slid it up and it stays there
, on the drivers side i just sat the crossover in the hole behind the left foot rest thingy!!
I would think that when you get some time you should make wooden spacers for your splits, this is what i did, the sound of the speaker will be improved, as it is sligtly more sealed and it has the wood to reverbarate through, rather than just 'free air'