Hey guys, I have a 2010 3.5l sxt awd with roughly 51,000 miles on it. The only mods are a flowmaster super 40 and I cut off the resonator and put on a straight pipe. I was just wondering what the normal idle rpm is. On a warm engine, mine seems to fluctuate around 600. Occasionally it will dip down to around 570 or 580. Sometimes I can feel a vibration from the engine as well. Is this normal?