Re: Mid Range opinions.
Put as much of the budget toward the front speakers as you can, even if it's all of it.. Then decide if you want to replace the rears. As for a suggestion, PHD has a heck of a line up. Check out the vids in the PHD vendor section for a taste.
CDT carbon fiber 6.5" mids & DD T2 tweeters on a Polk Audio PA D4000.4
SP4 15 w/ Tantric SHD softies on a DC 5.0k
2 runs Monster Cable 1/0, SounDrive rca's, Singer 310a 6 phase, Exide G78 under hood XSD3100 rear, plenty of deadener