Rear Deck Speaker Popping/distorted. Options.

So everything on my car is going to stuff at the same time lol (radiator just went, also blew out my right HID cause coolant went everywhere, window switch broke wouldn't let me close the window).  All of a sudden my rear deck speaker (driver side I believe) started popping, maybe the cold did it in, maybe the bass boost on my JVC HU.  

So the whole system sounds decent with the JVC head unit, did this speaker go because its 15 years old?  or because I abused it?  This is the HU I have http://www.amazon.com/gp/product/B00B8YTOZ4/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Max power output is 50w x4.  The reason I ask is because after searching I realize there is no direct replacement 8" speaker to drop in their place, so I was thinking of just buying new ones but apparently they are $175 a piece from the dealer or $55 for used ones on ebay but Idk how "used", probably 15 y/o used and ill just blow it out again.  

So I was thinking getting 3 sets of these fron doors, rear doors, rear deck

http://www.bestbuy.com/site/polk-audio-6-1-2-coaxial-vehicle-speakers-with-bilaminate-polymer-composite-cones-pair/8804054.p?id=1218895847094&skuId=8804054

But they are 6.5", so Im guessing they would be a downgrade from the 8" speakers in there now?  Another option would be 8" free air subs, and I guess I would have to bite the bullet and get an amp.  And get 2 sets of the 6.5" for the doors.  Tweeters in the dash seem to be fine, so Ill leave them.

I figure if im replacing speakers, may as well do the doors, my driver side door speaker cuts out from time to time anyway.

Thoughts?  

Thanks!