I took a look in the cda-9813 manual and it says that you can run in 3 way mode with
low range speaker - 20 Hz - 200 Hz low pass
mid range speaker - 20 Hz - 200 Hz high pass, 20 Hz - 20 kHz low pass
high range speaker - 1 kHz - 20 kHz high pass

As far as I understand the manual, it looks like it, in 3-way mode, uses the rear channels for the mids, fronts for highs, and subs for lows.

I think the 20-200 limitation comes about in 2-way (f/r/sub) mode

Not that I have actually tried it.

 

As someone who has ridden around w/ no trunkliner pieces because of a stereo install saga, I've got to tell you that getting better speakers for the stock HU is not going to net you much of an improvement in sound. Yes, the sound leaving the speaker may be better, but the harshness of the environment will negate most of the gains. My passenger seat is removed as well... lots of noise from that floorpan. And you've also removed the dor panels?

Just my $.02.


Add'l comment: From the list of mods in your sig, I would also assume that you've been to some kind of professional driving school. THAT is the best way to shave time!

 

yup, you're right. i simply forgot that a lot of the upper 2003+ Alpines added the 2-way and 3-way crossover option. my bad.