Re: factory wiring question (vwdoink)
I can not prove this, but I don't think there is a crossover exactly. Many oem stereos use the natural roll-off of the mid-woofer as the lowpass and place a capacitor across the leads of the tweeter. This is not the best sounding, but it is reliable (fewer components to fail and cheaper). You may notice a small capacitor (often yellow or blue in color) mounted on the back of the tweeter, intended to block damaging bass from the small driver. High frequencies will not usually harm woofers so there is no need for an external coil.
Again, since I have no experience with this car's system I cannot swear to this.
[Modified by cchristensen, 6:34 PM 11-26-2001]