Hmmm! My thanks to the OP who did the original experimentation and found the solution. This may well be the only thing I "mod" on my SRT-6. In addition to being a car nut, I'm a 30 year card carrying audiophile. So when I first listened to the sound system in the Crossfire, it sounded horrible to me. My solution in the first two weeks of ownership has been Bass -3 and Treble +3. It makes a difference. But, as the OP pointed out it's a crude fix and not really satisfying. This quick filter fix seems to make a lot more sense than rushing out to spend gobs of cash on new equipment.

I couldn't believe the post from the guy who wanted to put two 12 inch subs in the rear. OMFG! You've got to be kidding. More Bass? Also can't believe that some people are lamenting the reduced "bass" output from the doors. To me it's just obnoxiously unbalanced. But I suppose it's a taste thing. If you like hip hop and enjoy sharing your vibrating car with everyone around you, the crossover modification will likely disappoint.

The Crossfire is a really small environment and the factory Nav radio has plenty of power. It really is just a spectral balance problem for me. I'm not certain I'm in love with the door mounted tweeters but I don't think it's really possible to tell until I can get the Bass/Midbass sorted out. I wonder why the designers chose this sort of balance (or imbalance)? Most cars of 2005 vintage had this sort of thing pretty well sorted out. German hip hop engineers? European techno punk?

I didn't read this entire thread, has anyone investigated a high pass filter for the door tweeters to keep low frequencies from over loading them.