ZFE

Hello everyone, just needing some help with my 2004 Avalon. It has the 4 speakers (2 front & 2 in the rear deck, plus the 2 tweeters. I would like to upgrade my headunit and all the speakers. I’ve measured them and come to the conclusion that they are 5.25”. I just want to know if anyone has gone bigger in the front and rear and what I’ll need to upgrade the entire system including the headunit. Thank you.