Any ideas why the front door speakers and tweeters are wired out of polarity?

 

Maybe a little easier to follow like this...

 

Looks like they are wired in series,which would explain the wrong polarity.

 

Nah, they're definitely wired in parallel. Which is surprising given it's putting a 1.5 ohm load on the amp between the 6 ohm tweeter and 2 ohm door speaker. Wouldn't have figured a stock amp would be stable at 1.5 ohms.

I replaced both with 4 ohm speakers, so it's a 2 ohm load now.

Anyway, I did some research and it sounds like it's actually pretty common to reverse polarity of tweeters and mids. It's done to flatten out the frequency response and improve staging.