What to do? Help me pick...

You could do the 408 and a lot of other stuff for the price of the 5.7, and it would sound more cool.

HOWEVER, if money were no object and I was gonna drive one a lot, I'd slap in a 5.7 with the matching trans, and take advantage of the higher mileage, A/C, less problems with fuel, etc. I've got to think that setup would run really good in an A body that is 700 to 1000 pounds LIGHTER than a current Charger