OK, since at some point down the line I'd like to replace my entire stereo system with a nice aftermarket one, I decided to fix this the least expensive way possible: I removed the rear speakers (which weren't crackling) and installed them up front.
I had to snip the wires going to the rear speakers because the connector is different than what's up front. I put some electrical tape on the ends of each wire.
As for how I worked around the amp issue, I opted for zip-ties. I tightened them up as much as I could and the amp stayed in place well. Notice I used nuts to connect the wiring from the amp to the wires coming from the connector on the speaker.
The assembly is now in place in the front door.
Everything I described above was done on both sides and I tested my new setup before putting the door panels back on. The end result? I can now listen to music without crackling speakers.:happy107: The bad news is I've no longer got sound coming from the rear.:icon_frown: I'm actually OK with this as the sound I'm getting from the tweeters in the dash as well as the speakers in the front doors is good.
The total cost? $10. The door panel remover was $8 and the zip ties were $2. I already had snips, a wire splicer, wire nuts, electrical tape, and a phillips screw driver. Oh, and guess how many door panel fasteners I broke throughout this job? Zero. It's amazing how much easier (and effective) a job is when you've got the right tools.
THANKS for everyone's input. Two important things I learned throughout all this are:
1) How great it is to have a forum like this with people willing to share their knowledge and experience.
2) It wasn't that difficult. When it's time for a nice aftermarket system, I'm installing it myself.