Surprisingly, kick panels installs are considered one of the best locations. Also most coaxial speakers have directional tweeters.It’s been a long time since I was into car audio, but I’m not sure you want two-way speakers with tweeters in the kick panels. That will draw your soundstage down. I would keep the mids/highs up on the dash and use the kick panels to provide the lower-end which can’t really be localized anyway. I would even put a low pass filter on the kick panel speakers.