When do you need subframe connectors

I installed a complete Hotchkiss system on my 69 Dart. It is a COMPLETELY different car, does not even remotely resemble the way the car handled before I did it.( It's like on a rail now!)
One thing I have noticed is a lot of "creaking" and "crackling" noises. Nothing irritating and just when I go over transitions like a drive way entry or speed bump. My take is that the car can't move where it used to and eventually those noises will go away. (They really aren't alarming ,just a different sound than what I had become accustomed to)
Worth every penny, DO IT!!!!