You may be right. I've been driving my Explorer around these past few weeks and have gotten used to leg room! I hoped inside the S tonight and man, building kick while mantaining legroom and remaining asthetically pleasing will be nearly impossible! I can do audio, but I am no custom fabricator when it comes to car interiors and those upper range drivers cannot stay in their factory locations for proper imaging.

 

Sounds like a pretty challenging project that you are undertaking Looneybomber. Would definitely love to hear more about the progress of your project! Have you considered the location beside the oem speaker location? I haven't measured it and the window may be in the way, but that'd another place I'd consider putting a midbass aside from putting it the oem location and building a kick panel enclosure for midranges.

What about "on" the dash with some cutting and a custom enclosure? It may be a little crazy and I haven't checked how much room there is underneath the dash, but a friend of mine had a shop done that for their boxster - midrange & tweet on dash and that worked out fabulously.

Other than these, I couldn't think of other "sensible" place to put another pair of 6.5-7" speakers without compromising SQ significantly.

Midbass really is a tough problem to solve from my experience in the S. After doing some research and realizing how difficult it is to get great results, I ended up replacing my HU with the Pioneer Premiere P880PRS which has a dual (separate L&R) 16 band EQ and guess what, a Auto EQ!!, so easy that a caveman can tune the system. It also have time alignment settings so you can set delays for individual speakers. This HU can also support up to 3 amp, driving high, mid, low frequencies and many XO settings. This HU may hit a few of the requirements you are looking for at a reasonable price. I sounded like a Salesman... and the midbass - yes I use the EQ to compensate for it. It's not ideal, but the results are satisfactory when I'm listening to it while driving. Btw, this unit also quiet my passenger's complaint that my sound system sounded funny, because I can change the settings on the fly to favor both driver and passenger when someone sits in the car, rather than the usual fixed "driver" only mode which I'm guessing "most" of us favor... who cares about the passenger right? :-)

Where are planning to put the tweeters?

 

Oh, that sounds like a nice HU. I may have to take a look at it. As for the tweeter location, I will likely not be able to put them anywhere except below the dash because the midrange needs to be close to it. There's not enough room above chest level in the car to put a tweeter and midrange without doing more surgery than I'm comfortable doing.

Ideally I'd like to build removeable kick panels, for when I sell the car, just incase the next owner doesn't like them.

I'm not putting any money into this project right now since I am trying to sell my car. I'm just gathering info, brain storming ideas and using what things I have around the house right now. If it doesn't sell for what I want out of it, I'll keep it and work on this audio project this winter while I have it "tucked in" the garage till spring.