FWIW, I fully believe that installing an aftermarket one is NO harder and MUCH cheaper than a Mopar one. I believe (though not sure) that Audiovox makes the MOPAR one.
I can provide assistance on an aftermarket one. I currently have a DEI 562T in mine. You could do a 561R also - I like the 561T as it has dedicated lock/unlock buttons and a dedicated aux button that I'll have run the lift glass.
If you look to price it out, you'll need:
1) 561R or 562T (or whatever other one you want)
2) The 556CW (or C, same thing) or similar to bypass Sentry.
3) A pair of relays, a 456L (haven't gotten mine to work yet though) or other single-wire door lock module.
My costs were $75 for the 562T, about $20 for the 456L and $20 for the 556C.
I like DEI. I've done a few of those, and 1 Bulldog. DEI does a better starter IMO. Smaller, and less perihperals needed.
Also, you can get a grey-headed sentry key for like $20 shipped off ebay and ditch the stupid integrated key and fob.