2007 Vibe, base, 5 speed. The upper grill was covered 100% with duct tape and a coroplast belly pan was added. The bellpan went back to just-before the cross member behind the engine.Results WITHOUT the grille cover & belly pan.Idle 58db2500 RPM (same RPM as 65MPH) (not moving) 64db65MPH 75db (asphalt) 80db (cement)I changed the oil (5-30 full synthetic) and put the grille cover and bellypan back on. The car was also washed Repeated the above conditions.No change.Test was performed with a RadioShack digital Sound Level Meter, catalog # 33-2055 using "A" weighting. Meter was held in front of me, just above the center of the steering wheel with the microphone pointed up and slightly forward.