I've read that removing the rear panel which covers the rear speakers, sub, etc. on the ZR would break the attaching clips that then must be replaced..? Anyone do some custom audio work on their ZR that can confirm or deny this?

 

I know this thread is 8 years old, but at least there will be a reply for others to read.
The answer is "yes" you can replace both rear speakers without breaking the clips. Just be patient. I replace the rear speakers with new ones that have 90 oz magnet and they went in without a problem.
So patience is the key here