@C908
From what I understand there's nothing different about the R3T and R3R engines except the tune. Exhaust, transmission, and drive are all the same. You should be able to get all the power back after getting the cable and uploading the proper drivers for a stock R3T. Then if you're looking for a little bit more you can make changes to the air intake, and exhaust (The TORS slip-ons give her a nice growl and are cheap). Of course these changes will again require additional tuning tweaks, but unless you go off the wall you'll probably be able to find someone else who's set up the same config.
So when it comes down to it, it's just the details that matter between the two models. I liked the aesthetics of the Roadster better, and the foot peg positioning gave me the impression I could ride her a bit more aggressively. However I've also got some Hardstreet bags, the tall sissy bar, and the same screen Rick and Mitzy have on her. As others have said the R3T comes configured for longer rides, but at heart its the same bike and is easily capable of as much raw power as the R3R with very little effort. The best advice I can think of is to find one of each version, sit on it, and see which one speaks to you.