If you're looking for power, then look to swap in an engine that will definitely fit. Look into either a M112K (SRT6), M113, or if you want to go for it, a M113K. All of these options are much easier to accommodate than the Ecoboost or the 4.5/5.4 or 5.0 options, and all are capable of the power levels you are looking for. FWIW, I was looking to swap a Chrysler 2.4 turbo from a SRT4 into a Crossfire, before just going this route, myself.