I currently have HLCD's. Pat (Unnerv) has them as well in his 99 CSVT.
With adequate equalization and proper mounting, they will sound amazing. However, like Tony said, it's a unique taste.
I'm in the process of relocating my midbass drivers to the kick panels. I'm tired of the vibrating I'm experiencing with my front doors.
This is going to be a challenge because the drivers for my HLCD's are huge! I may have to down size to a 5 1/4" midbass driver to make it work. We'll see!