I had to use a heat gun to push in the Q Logic at the emergency brake,but that was not completely satisfactory. They are NOT designed for mid bass or bass speakers as they are rather thin ABS plastic with no backs, so the body of the Q logic will resonate and the backs will leak, tending to distort and cancel bass. There is a reason people use MDF for cabinets and for having enclosed cabinets. I believe that all three speakers, bass, midrange, and tweeters, should be close together as possible, as is done with home speakers. I realize the door panel can work pretty well, but I do believe the mid bass is directional enough that it should be aimed the same direction as the mids and highs.
I know this from my work in audio with Bob Carver (founder of Phase Linear, Carver Corp, and now Sunfire Audio) and Greg Mackie (founder of Audio Control and now Mackie Design). This means custom kick panel boxes as far as I can determine. Also, I plan to install a center set, eliminating the cigarette lighter and likely the lower din mount. I plan to move the AC control to the upper DIN mount and have the stereo head unit where the AC now is. I may even move the AC control to where the cigarette light area is. That would open up the entire DIN mount area for some serious center channel. Audio Control makes a unit which will provide a true center channel.
I am kind of a stickler for a home audio sound in a car. In fact, I wanted Bob Carver to help me build a super car amp in 1961, but in those days it was well nigh impossible, what with tubes and the state of electronics then. So, in 1966, I asked him to help me build a home super amp instead. It was later that high power car amps became possible. I know a guy who used home amps in his car, using a high power inverter. Sounded awful nice,but, again, front speakers were the Achilles heel there too. I don't like today's stupidity of overwhelming bass as an ego trip and an attempt to compensate for inadequate front speaker sounds.