LS powered Duster, Abomination or Go For it!

Personally, I’d say stay Mopar, but
It is your car, but for God Sakes, don’t put a cowl induction hood on it just kidding, you gotta put up with the comments, not me.
Staying Mopar will
Cost you more money
Cause you more headaches
Test your skills at finding parts.
Give you the pride that comes from being a little more exclusive

Staying mopar will cost him more money than an LS swap?

I don't think so. Put a 5.9 magnum or LA 360 and go have some fun on the cheap.