My experience has been that a combination of 315s and TRex/KORE coils significantly reduced any vibration I had. Most importantly is to make sure the bigger tires are balanced properly. The change in pinion angle up front with the taller coils helped, I am sure. Here's my quote from page 3 in the other vibration thread:
"I had the cyclic thrumming vibration, stock truck. Put 315s on, still had thrumming, add shimmy. Took out front drive shaft, vibrations reduced only about 50%. Reinstalled drive shaft, added TRex coils. Thrumming severely reduced, shimmy still there. Added Innovative Balance Beads, shimmy severely reduced. In all, I still have vibrations in that "sweet spot", but engine vibes seem to equal all other driveline vibes now. Not 100% happy, but it's tolerable. "