looking to buy a bolt on 4 inch suspension lift for my 89 4runner, and have a couple of questions. each lift is for either 2.5" or 3.25" u-bolts. i'm assuming this is the distance across the top of the u-bolt, but does that mean that there are trucks out there with wider leaf springs?

are there any important differences between the pro comp, trailmaster, rough country or superlift ifs lifts? superlift and trailmaster and rough country have one piece drop brackets vs pro comp, but i know a lot of people are running the pro comp. looking for some first hand experience on this one.