1999outback

Hi folks, sorry about the duplicate woofer postings, computer froze and wasn't sure the first posting went through. I was wondering if anyone out there knew how to completely and safely remove the door panels on a 1999 outback wagon in order to replace the speakers, and if anyone had any tips on doing so. A few weeks ago, while driving with the stereo on the front driver's side speaker (not sure if the back driver's side door did this as well as i was s=the only one in the car) a high pitched squeal began coming out of it. This squeal responded to the volume control and I was able to turn it up and down. It squealed regardless of the source of the audio (cd or radio). After 15 minutes the sound came back but the bass notes were distorted, sounding like someone crumpling up a handful of cellophane and foil. I assume this means the speaker is blown. The back driver's side door emits no sound, and I am not sure if this is due to the front driver's side speaker being blown and signal being interfered with, or if it did this when i bought the car ( I was given the car by a relative who mostly listened to oldies, little bass). I would like to buy a new set of four 6 1/2 speakers and replace all four of the factory speakers, and leave the front mounted smaller tweeters alone. Any help? I'd hate to get the panels off without knowing what to disconnect or remove and crack something.