One of the first things I did to my Fifth Avenue was a set of matched cop car bars. Car originally only had a front 1 1/16" bar. The cop bars measure 1 1/8" and 0.75". It made a huge difference in regular street driving and changing lanes on the interstate. Honestly, it made it safer to drive.

If I was daily driving and old car I'd match a set of big sway bars and go soft on the torsion bars.