Not sure what oem stereo you all have as I know that there is at least 3 different systems from the factory.Wiring is all different, especially SR5's.
I have the JBL system and what they did on it is put crossovers in the amp or on the speakers that gave the dash speakers only high and mid range frequencies and the doors only mid bass. My doors came stock with single cone 6x9 midwoofer speakers. That's how they got the pretty good sound staging like a good component set-up with fairly cheap speakers. Highs and mids bouncing off the windshield with the lows down low in the doors. I hooked up a JL Audio co axial in my door to see and no highs came out of it.
They don't make many 6x9 midwoofers so I went with a 6 1/2 inch midwoofers from MB Quart(PVI 164) that have a 250hz crossover made for a component system. Wish the sensitivity was a little better but my Pioneer has an equalizer which helps.
MB Quart PVI 164 in the door