04 had the chimes separate from the Radio iirc. The chimes are attached to the radio not the amp from 05-08.
OP. How much experience or skill do you have? Did they properly adapt the radio in or hack it in? I see you describe the amp as a hack job but that is easily repaired if you know what you are doing.
All this being said, if you have to essentially rewire the whole thing anyway, and you have the funds, go new. The Monsoon system is a pretty good system from the factory, but limited and mediocre at best when trying to customize it.
If you want an amp, look into reviews for a good 4 or 5 channel amp. I prefer component systems but you can get passable/great sound out of specific coaxial sets. I recommend Infinity REF 9623 or Infinity Kappa 693.11i. If you go this route, I would also get a sub. A single 12 or dual 10s is more than enough for a pleasurable experience without shaking the car apart. Also, DYNOMAT too many people who do this job themselves do not properly mat their trunk/rear deck and doors and the car sounds like garbage due to reverb in those areas.
Also keep in mind, an amplified system can and often will require the use of capacitors or at least a better alternator depending on your current output.
Estimated costs based on current crutchfield without misc. Stuff.:
AMP (5channel) Soundstream Picasso Nano- 200$
Front speakers 120-200
Rear speakers 120-200
Subwoofer and box Rockford P1-1x12 140
Total: 580-740
If no amp, I would still run new wires. If your head is a good unit get some good speakers and and wire them in. Monsoon systems come with a center channel, you can either wire it in, or delete it. You can also start here and prep for future upgrades.
No Amp cost:
240-400.
Disclaimer: if you don't have experience rewiring speaker systems, find a friend who does or bring it to a professional. Learning is great, but electrical gremlins are the stuff of nightmares and a bad splice or ground can cause hours/days/weeks/months/years of frustration and troubleshooting.
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