Hi, I'm about to install some new speakers (with "crossover") into the stock positions in the doors. (Non-HK system.) I was wondering, do the stock components have a crossover? I didn't see one when I had the woofers out previously, but then again, I didn't even look at the wiring that feeds the tweeter.

I guess all I want to know is whether the wire going to the woofer carries a full-range signal. Can I hook my new crossover to that wire, and be able to drive both the woofer and tweeter? Or alternatively, is the wire running to the stock tweeter full-range as well? Perhaps with just a high-pass filter mounted near the tweeter itself?

The new speakers run the woofers full-range, and only filter the signal going to the tweeters. I'm wondering if that's the way the stock speakers are wired as well...

There's a single tiny capacitor on the side of the tweeter.
One pair of wires goes into the door, direct from the back of the head unit, and feeds both speaker positions.

I am about to do the same but the box for my speakers said that if there is a factory tweeter in place it should be unhooked to prevent damage to the new speakers. They are Alpine 17c2 speakers.
Second how can I tell the positive and negative wires from the factory harness? Does it matter as long as I use the striped wire for negative at all points?

Can't imagine any way the original tweeter can "damage" the new speakers - but you might want to remove it to make the sound "purer" with just the new speakers doing the work.

As for polarity, some crossovers need +/- correct to work properly. You might find the original speakers have +/- marked on them. This MINI2 FAQ picture has wiring colors at the head unit, which might or might not match inside the door ...

Sweet. Thanks, GBMINI. It sounds like I can put my filter "in line" with the wire that feeds the tweeter. (It's just a cap and a coil.) I'll be able to leave the wires that are feeding the woofer "as is".