If I mount the crossovers in the pillar I would wire into the skar crossovers that will be mounted in the doors, and possibly wire both tweeters on each side to the crossover.
I needed new 6.5 's but the oem tweeters are lacking, when I plugged in the skar tweeters, wow made a huge difference, I hardly have any sound from oem tweeters, unplug oem tweeters and plug in the skar 's and it is a night and day difference.
Need to double check on wiring the crossover, I am used to just 6 ports on crossover 2 in, 2 out of mid and 2 out for high, but these crossovers have 8 plugs.

2004 crossfire
Kenwood kmr-d558bt
Mb quart 2 x 1200 watt ab amplifier powering 2 skar 8" vvx subs.
The skar tx65c componet to factory amp will be a nice setup for my hours of driving.