Check junkyards in your area. If going from the 5.0 to the 8.4 the swap is easy. You just need the dealer to reprogram everything. Make sure to get the VIN of the vehicle you got the radio from for the unlock code. I also did this and only spent $350 for the radio and bezel from a wrecked 200S. RA4N is the preferred radio, you'll get a service vehicle phone message but if you Google hard enough you can find a way around this too

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I think any RA4 should work, when you flash the newest SW mine figured out that it was a Chrysler, it originally showed it was an SRT (took about 20 mins, the radio reset and everything came up Chrysler).
I'm not 100% sure but I think the dart radio is different.
I can try to answer any specific questions for you guys as well.