Mid range normally help improve sound staging, you can put it on you kick panel by customize the kick panel but the sound stage would be like kinda low.
The best place to put it is on the A-Pillars with the tweeter. That would really enhance the whole sound stage.
To do that, the A-Pillar have to customize, modify it, mould it (sorry for my english).
A lot of competitors that compete in SQ competition are doing it. Running this 3 way in front is superb.
If you want to see how it actually looks like, go to kfaudio.com. View its honda jazz. I think the picture is there.