My box has TRD springs on it, presumably dealer-installed. Would I gain much drop by switching from 4 year old TRDs to new DF210s? If it's not much of a difference, might I be better served by saving my pennies for an air setup later?

FWIW, I am considering Echo struts, if I go the spring route, because my xB is clearly not low enough. I totally intend to spend my recent raise on car things, naturally.

 

DF's will get you to around a 2"+ drop. your TRD's are around 1".

 

You'd gain a lot of drop and a smoother ride. Go for it.

 

df210's are a lot better