Some more Lift questions!

Ok, so after looking through many posts and checking websites here and there I think I have a idea on how to lift my truck. I have decided on the the bilstein 5100 that many people use here. But I have questions. I breezed over some of the forums and I was curious on springs. If I set bilstein 5100 to 2.5" and use stock spring does that mean the spring is in a constant state of compression? Are 3" springs designed to give an additional 3" of lift or are they used for a truck with say 3" of lift? Also, are new wheels necessary or can I get away with stock TRD OR wheels. I do some occasional offroading when I happen to get a weekend of but nothing to crazy. I'm trying to save money where I can but I dont want to deteriorate the life of some suspension component. I plan on running the stock rugged trails for as long as I can then maybe installing lift/tires at the same time. So any imput would be great. As I said i breezed through some threads so sorry if this is repeating anything.

08 Taco AC TRD OR pretty stock atm

 

New wheels aren't needed if you want to run 265/75/16.
You will either need wheel spacers or new wheels with a 4.5 backspacing at least if you plan on running 285s.

 

If you plan on lifting in the future you might as well save up and do it once versus buy some billies, find out you have a harsh ride, then upgrade again and again. Also depends on what you plan on doing with your truck, Mall crawl, Desert race etc....

 

I don't really plan on lifting it later. I just want it done right. If I have to wait i'll probably just wait and get a icon stage one or 2. Also a question about aals, my brother was moving some dirt in my taco when I guess the truck started rocking. Since aals are a bit stiffer, will that fix this?