I'm a new xfire owner and I purchased a limited roadster. I researched both and tho the srt 6 would be more fun to drive the fact that production has stop on these cars made the ltd make more sense. Repairs & parts will become scarce and expensive and since the srt 6 is a special edition parts may not be available down the line. Plus cost of ownership is less in the limited, and they're fun to drive also. The difference is a dragster vs. a track car.
Love my Limited!! And I drove the srt 6 loved it too!