There was a time when swapping out engines wasn't too hard. Of course, in those days there was room to spare under the hood and the main concerns were motor mounts and mating the engine to the tranny (not to mention finding out if the suspension will hold up the added weight). You still have those concerns plus (as previously stated) the engine control unit (ECU or brain) has to come along with the new unit, finding out if the fuel system can handle 2 more cylinders, figuring out if the driveline (rear+front if it's 4x4) will handle the added torque, etc, etc, etc. If all that doesn't slow you down then (also, previously stated) anything can be done for the right price. Good luck.