Rubber or Urethane???????

[CRGRS 66]

I need to be ordering cab mounts and trailing arm bushings (hence this is in the suspension forum) soon.

My set up in the front will be 2.5" drop spindles and 2" drop springs (otherwise stock setup), and my rear suspension will be a porterbuilt stage one bag kit with porterbuilt adjustable trac bar. No notch in back, bags are just to adjust ride height if towing, or carrying a load. Should be running around equivalent to a 3" or 4" drop.

I am inclined to order the urethane kits, but would be interested in hear opinions from you guys who have used one, the other, or both.