Thinking About Some 5100s

So I took my truck in the other day for an oil change and got a call saying my rear shocks are have a small leak and my fronts are old. So I now have an excuse to get better shocks. I know I want to get 5100 because that's what everyone on here has said to get. I'll be using the factory springs because I'm on a budget and they are compatible. So I have a few questions that I haven't been able to find the answer to. I'm wanting to set the 5100s at 2.5 inches.

1. To set the 5100 at 2.5 inches will I need new UCAs? I've read you have to and you don't have to.

2. Could I get away with 2" lift blocks in the rear? Would that make the truck sit level? My taco has 3 leafs (not sure if that is relevant).

 

My shop measured my truck and 1.75 in front made me sit level. I did nothing to rear so if u do max 2.5 and then raise rear in theory youd be back where u started but a quarter inch off level? Right??