I don't see why not. Both cars are built off of the LH Platform. Both should use the same transmission (42LE). The later Intrepid R/Ts used the same engine as the 300M's.
I don't think you will end up needing a ton of parts to complete the swap. Engine mounts, ECU's and radiator hoses will likely be different though. I would head over to the 300 Enthusiasts Club (http://300mclub.org/index.php) to be certain though. This link might also be useful- http://www.dodgeintrepid.net/forums/
