When we first bought the car the engine was quiet, you could just barely here it and the exhaust note. Now with 123,000 miles the engine is very loud and I can barely hear the exhaust note anymore. Most recently I replaced the plugs and pvc. Of course, had to remove the intake. Oil is regularly changed and tranny fluid was also changed. Could I have missed something on the intake that may cause the excessive noise? I also cleaned the throttle body. Could the catalytic converters be a little plugged causing more engine noise than exhaust? Seems a little sluggish when accelerating.