Track Bar ends bolt torque?

I have a Rusty's HD track bar with the rubber bushings at either end. Should I torque the bolts down tight squishing the rubber or only keep it snug so the rubber has a bit more flex? I noticed that when fully torqued with rubber squished tight that I get more low speed creaking noises on turns and bumps.

My book says 55lbs,and you want them as tight as possible.