We have yet to try these out as of yet, though we are hoping to get them on one of our project trucks for testing soon. On paper, the lower-rated Blue Springs will ride less stiff if your axle does come into contact with them than the black. In theory, you would be fine going with the 1000lb-rated springs, though you would get less sag with the 1500lbs springs, since they are a touch stiffer.