Yes, it fixed the lean after installing OME 883 springs.
Yes, the stock studs were long enough.
Like others have posted here in the past, it is hard to notice the lean (OME 883 w/o tp-14 spacer) without measuring both sides. However, I like to know that things are level and square, so I installed the spacer.
I have the 885/895 and I had the option to use the 5mm trim packers from OME although I decided to just put the lift on and see how it was. The truck is perfectly level on both sides. It really just depends on the truck, aftermarket additions, and lift variance. Try the trim packers......... $8.00 but the labor would be kinda expensive to take the strut and shock off.
Mine has the TRD springs and I really don't want to replace them. It sat about an inch lower in the front from the factory and now that I added the DO bumper and winch it sits about 2" lower (2.5) on the driver's side. The suspension is sitting real low, the CVs are angled up slightly. I am putting 2" toytec spacers in and the 1/2" spacer on the drivers side. Hopefully then all 4 corners will be close to the same height and the CVs angled slightly down from the diff.