socal: This is the information you'll never be able to pry out of Dodge. R/T chrome clad wheels to SXT. Bolt pattern... offset... hub bore size all ok. The only snag you come up with is on the rear wheels of the SXT (for sure on the 2 wheel drive). The hubs are slightly different. The hub centers do not have a completely round opening in the centers. They have a rectangle opening inside the round hub that the wheel center goes over. The problem is the R/T 20" chrome clad wheel has plastic clips around the inside of the wheel center. It's only purpose was to hold the chrome clad in place on the wheel while the industrial adhesive sets up during manufacturing. The problem is those clips won't fit into the rectangle cut out in the hub. Solution: Use a dremel with a little cut off wheel and wack off the the little plastic clips. Then everything fits perfectly.
Shark: Thanks a lot!
Dayley: The ride is slightly stiffer, maybe a very little bit rougher. If I was going to give it a number I'd say about 5% stiffer... definately not as high as 10%. I'm not racing it around but I did do a few hard corners at speed just to see if the handling was different. The bigger and wider wheels do keep the truck more straight up in the corners... takes away a little body roll. I guess that's better performance... if you ever use it.
Ending conclusion: The 20" wheel look in my opinion is pretty awsome. I don't think that ride comfort suffered that much at all. From a performance standpoint I think all the stock wheel set ups are good for this vehicle (and remember I had the smallest 16" wheels on before). If you were really, really pushin' it into corners I suppose the wider footprint on the ground and the taller, lower profile tires would nudge performance up a tad. But bottom line for me was I just liked the look of the stock R/T wheel and wanted to see if I could actually find a set without paying a dealer crazy money.