Poly Cab Mounts vs. OEM rubber/ torsion bars/ dash question

2011 Columbia Day Cab

Is the added price of the poly bushed cab mounts worth it? Anyone tried them? If so, is the NVH difference noticeable from stock?

My torque arm bushings are looking a bit squished out and dry rotted. I picked up a set for the drive axles and was going to swap them out but am concerned about an alignment issue after replacing. Had a three axle alignment done about 6 months back. Does alignment need to be re-checked after replacement?

Something I noticed recently on my dash. I put the key in and turn to the right ign power and allow the computer to run through its checks. Typically within a few seconds the gauges would do a sweep and return to zero and then I would start the truck. I've noticed that for the last few weeks that sweep of the gauges takes almost 10 seconds to initiate. It's weird and I'm just wondering if that's a sign of a pending issue. Note* If i turn the key left to aux and then right to ign power it will sweep the gauges immediately like it used to do just turning to the right before this started.
I was always told not to start the truck until it's run its precheck and the gauges return to zero but this extended wait time is annoying. New MCM by the way that didn't do this when first installed.

 

I might have misspoke. I'm not changing the bushings in the arms but replacing the whole arm and bushings as a unit. Still no alignment needed?