One thing that needs to be considered, is, IF one needs repairs on that VM engine that the dealers will have parts to do the work. The Liberty's with the VM have had a hard time being repaired be cause the lack of necessary parts. My sons Libby was delayed being finished cause the dealer was sent three different sets of gaskets, three different times and each was the wrong ones. Don't know where they were sent from, but hopefully they will have there ducks in a row now.
Plus the new VM will have IGNITERS for cold pre-starts. Why I mention this, is the 4 bangers would break on removal when replaced.