I chose to mount the 6-inch mids and tweeter in the kick panel where the air vent used to be. To do this I need to block the old air vent hole in the kick panel and make an enclosure for the speaker. This problem stumped me for a while until I found some 7-inch salad bowls in the supermarket! They are the perfect size to hold the speaker and were only $3. I cut some 18-gage sheetmetal to close out the old kick panel and then welded the salad bowls to the sheet metal. Who knew? I guess you people, now.