Putting components up front with the tweeters in the sail panels rather than stock locations is about a 200% improvement in imaging as well.
I ran for 6 months with my tweeters in the stock location then I moved them one day and couldn't believe the difference...
I also haven't had the rear speakers faded in since January...I faded them out when I was checking levels with a RTA and never faded them back in. I didn't notice till a passenger asked me to turn on the rear speakers for them.
-- Dave