wonder which would be easier on the Z... place crossover in the kickplate area, or place inside the door and feed new wires through the door grommet into the dash for the tweeters?

is it easy to find the speaker wires in the kickplate area?

Kick panel much easier and they fit pretty well there. Plus right above that location it where the tweeter is so all you have to do is run a line to that from the crossover. what I did for the speaker wire if your running them off the head unit instead of wiring the stock wiring harness to the new one. You can take the aftermarket one form the head unit run new speaker wire form there to the crossover. Than from there to the new speakers. If it for a new amp run new speaker wire.

^^ thanks! :D