|So final results are:
a. LSD not even noticeable during daily driving with exception of reduced "body torque" when downshifting or upshifting
b. shims not needed. This was a direct bolt in application, but I was still glad I had an experienced rear end shop do the work to make sure the backlash was set properly and there is absolutely no whine or any noise whatsoever coming from the rear end.
c. LSD works very well. I have driven through snow covered fields in only 2 wheel drive and it is very easy to slide the rear around predictably when you get on the throttle. The unit also adds a feeling of confidence when darting into or across traffic or starting up in loose gravel or rain slicked streets. Tires do not chirp when cornering but I may experiment a little with the amount of LSD additive next time I change the rear end lube to see if I can get by with less additive.
Summary: If you've been thinking about adding an aftermarket LSD unit, this is a good way to go. Best is to order your truck with the factory LSD option and save $350 bux in labor (factory unit is only about $300 added to invoice), but by going aftermarket, you do get a unit that is pre-tensioned twice as much for better performance.
I picked up the LSD unit for around $300 delived to my door in the midwest from the west coast. The shims cost around $30 but you probably won't need them. The diff cover gasket was $8. The labor to install was just under $300.
So, for under $750 you can upgrade your truck to an LSD rear end and never look back.