I'm glad this question was asked as I am planing a bunch of performance changes to my '74 Runabout. I had planned on the poly bushings already, obviously the mustang II front sway will help as well.
I will still have to look into the front springs. The rear axle will likely be replaced with something sturdier, I may change up to 'Stang II shocks, plates, and sway bar.
This is definately the kind of info a newbie like myself is looking for.