What's your budget. The Firm Feels are the nicest. But the 73-76 sway bar is a pretty basic no brainer piece.
I would go with the $99 Ebay or whatever pieces. But you will have to do some minor fabbing for the sway bar to k-member brackets. Firm Feel will be a drop in super clean install.
For a 67-72 sway bar the Firm Feel is a better fit and has FAR superior mounting brackets.
Here's a picture of my $15 swap meet 1 1/8" front sway bar and mounting stuff.