New observation by what just happened to me, Nuke I just installed my body lift kit 1 3/8" and took my sporty around the neighborhood to check the tire clearance and I drove about a mile but without the front bumper installed and guess what for the first time my sporty almost hit half way on the temp gauge, I installed the original bumper back on after cutting out part of the black top "Reinforce beam" so you can get it all the way in and bolt the 4 12mm bolts and guess what the temp went back down to almost a hair on what it usually was, well it's not on the same spot but my guess is that those few holes on the bottom of the bumper are directing air to the bottom of the radiator and somehow it makes a big difference on the cooling of the engine, (placement)of bumper, correct me if I'm wrong but I think you changed radiator and bumper at the same time?

Well hope all is well and keep on sporting.