Falbz - did your Charger have a front sway bar? I head you need to make sure the calipers mount to the rear if it does. Also, did you have to get a larger booster?
Yes I did have to mount the calipers on the rear for the sway bar and clearance even though I'm not running one atm. I did mount them initially on the front but the calipers hit the sway bar tabs when fully turned. As for the booster I did swap out the midland ross one (power drums originally) to a new MPM Bendix style one.
These kits are not US made either. Part of kit, if not all, is from China. I did get a letter from RSD months later saying there was a bad batch of spindles and I could swap my set out if I had any issues. Mine have held up great though as they could not tell which batch it was. Luckily I've had no problems.