here's how the story goes... lets say (for examples sake) your stock height (new from the factory) is 12" from the ground. your stock bracket is designed for 12". now over time your rear end sags from the typical spring wear so now your only 10" from the ground. so technically your stock bracket is to big by 2" worth of play. so you put in the 2.5" rear spacers and your new ground clearance is 12.5".... .5 over stock... dont bother with a new bracket, the stock system will be fine +/- 2"-3". you want to put in a bracket that gets you as close to stock dimensions as possible. so with new rear springs AND a spacer lift on 2.5 it is not NEEDED... but personally i would recommend it... here's the math 12+2.5=14.5 (2.5" over stock)... with a 3" bracket it would be 12+2.5-3= 11.5 (.5) under stock dimensions... what is closer to 12... 11.5 or 14.5... 11.5 is closer so i would just do it. the closer to stock dimensions the more articulation and better ride quality will be retained. just a note: i would recommend putting in bump stop extensions 1.5-2" will be perfect (it will give you an extra inch or two of travel and articulation while still protecting springs from total bottom out. i would also extent the brakeline about 2-4 inches. i have seen people take their swaybars off (only while off roading) and get some REALLY good articulation with nothing but extended shocks, bracket and 2.5" spacer lift.
hope this helps.
