The Firm Feel rear bar is great!
I installed one on my 67 Charger.

The brake line is easy to move out of the way.

There are some that have had issues with the exhaust pipes getting in the way. Do a test fit with weight on and off the rear axle to make sure you have clearence before you start drilling holes.

One additional note.

You are probably going to need longer U Bolts to install it. There is a plate that gets added to the leaf springs for the sway bar to attach too and my stock U Bolts were not long enough. I got 4 new ones at a local spring and suspension shop for like $30

I will be replacing my front stock bar with a FF bar this summer.