No, I haven't felt the need. I do clean the throttle body frequently as well as use injector cleaner frequently (roughly every 6,000 to 10,000 miles), and I have ocassionally done the on the car cleaning. The throttle body cleaning seems to make the biggest difference.
The last time I did the chemical cleaning on the intake manifold, The cleaner did such a good job that it cleaned up the carbon at the y pipe joint to the point that I had a minor exhaust leak until the carbon built back up about a month later. I really doubt that there is much left behind in my intake.
