Lift question

So being a noob I've been reading countless threads on lifts. I'm a little confused on a few things. A lot of people are talking about what they have their Bilsteins set at. If you set if for max lift, what are you sacrificing? Also I notice that Bilstein and OME shocks go to 2.5", then you need a spacer for the last 1/2 ". Some people look like they have a slight rake without the spacer. I was thinking of spending the extra cash on an Icon stage one and drakar replacement leaf pack when I get my Taco. I read that the Icon stage one can be set up to 3.5" and the drakar leaf pack give a 2.5" lift. Will I need a lift block for the last 1" to get a full 3.5" out of the back? I know the Taco has a 1" lift in the back stock but I'm thinking if I replace it ill need another inch to get me to 3.5". I'm also guessing the icon is better quality for the money. Am I hitting the nail on the head or way off here?