To breach the firewall, I cut an 'X' into the rubber boot near the brake cylinder. This allowed the best path for the wire under the dashboard, and then to the rear of the car.
The cross overs were embedded in the baffle. I cut out a panel and mounted brass hinges for easy access after installation. I used the tweeter factory wire for the input as they were not linked to the factory amp.
Notice that the woofer and tweeter are in the same location as the stock units. the new tweeters needed to use the stock mounting bracket to fit. Had to cut out the speaker and knock out the magnet.