plumbers dope is rated to hold pressure, teflon tape is not. teflon tape is rated to seal stuff where say a gas like methane,propane, etc. is run thru so it doesnt leak out the fittings. i always use plumbers dope.

 

teflon tape or blue rtv silicone works

 

superglue

 

just weld it there its not like your goin to take you turbo off anyway if you do there is goin to be a hole any way