The highs are coming from the front doors. The tweeters and "twiddlers" are in the front door. There is some center stage speaker in the middle of the dash, behind the display.Oh and regarding your 5.25 speakers, there are definitely options. That's provided that you are not satisfied with them. It sounds like you might be however. Do you know what frequencies those are handling at this point? If they are only delivering "low" frequencies, where are the highs coming from? In mine, the 8" door woofers are paired with the corner dash speakers so as I build my system, I am developing a solution that addresses them "together". Just how I'm choosing to address mine. There are different ways to go of course.