Espo Springs 'n Things install feedback ***

Mine are +1" and have been installed for about 8 years now, though the car has been on stands for some of that. Pretty sure they have settled . I think your Dart looks much better. I like a little rake on a muscle car.

As for handling, I've never broken the rear tires loose without meaning to, even on loopy freeway ramps well above the posted limits. I'd be more concerned with the front end for handling. I had the k member stiffened, 11/16 tie rod ends, and a factory sway bar with poly bushings. I think it handles pretty good for a RWD thats 43 years old.
No offense at all to GMachineDartGT, he gives great advice on handling, but most will not push their cars to his extent.