Ok, my turn I guess. Let's discuss what exactly in a car causes spikes and dropouts in a car. I KNOW every vehicle has them.
For those who don't know I have a 2001 Accord 2 dr with an 8" sub/midbass in each door, a mid in the kicks and tweeters in the factory dash locations. To somewhat mitigate the 315 Hz suckout, I moved the xover point to around 400 Hz. I know Kirk has an Acura TL (same basic car) and he has the same 80 Hz hump (his mids are in the doors) which leads me to believe that location is causing the hump. Would be interested to hear other peoples thoughts, experiences, and observations.