Bilstein 5100 lift. When to replace UCA's?

Installing a Bilstein 5100 kit on my 09 double cab. I'm setting the shocks at 2.5" and adding a 1" block in the rear. No top plate spacers. At what point do I need to entertain replacing my UCA's? What are the downsides of leaving the stock ones on it? Benefits of tubular replacements? Thanks in advance.

 

You should be fine. If you can get the alignment in spec no need for new ones and as long as they clear whatever you're running for wheels/tires.
Once you hit 3" they are usually needed to obtain proper alignment.

 

After a little research, was thinking Toyo AT II's, 265/75 R16. Wanted to go as large as possible without causing issues or cutting.

 

as soon as you are unhappy with the performance of your vehicle's alignment