Loving the rear end swap.
What kind of measurements did you take to make sure everything was square and you'd be able to keep the rear suspension geometry accurate?
As I'm not familiar with either DODGE or MITSU cars; do these share a similar chassis or are you making it as you go? Looking at your install, I take it they are similar but the COLT was never suppose to be RWD.
Will you be caging the COLT to increase structural rigidity?
WIll you be tracking this car or is this just to see if you can do it?
I don't think your welds look too bad, plus that's what grinders are for