Can anyone tell me the best way to get this stripped screw out?

 

Use a chisel and chisel it on the edge in the counter clockwise direction... pneumatic or hand tool.

 

You also use a vise grip pressure plier to get it off.

 

 

dremel cutting blade turns it into a flat blade screwdriver fitting!
Works on rear cover torx screws for headlights too

Should remove the intake manifold from car and clean the egr system INSIDE the manifold itself
If the IACV is dirty = so is the manifold passage and ports
Take the time to clean return springs and lube inside the throttle and cruise cables

 

I would go down the dremel route, too. Or just anything you can do to cut a slot into it for a flat blade screwdriver.

 

who told you removing the bottom of it was something to be done on car?

 

I don't understand what you mean by that question. In order to clean the IAVC it needs to be taken off the throttle body.

 

They make screw extractors for reasons just like this: Sears.com

 

That does not look to badly stripped. Do you have a large phillips? Also, a trick is to use a socket phillips head so you can apply more torque while pressing down. Strips way less.

Like one of these:

 

when in doubt whip the vice grips out