By the time the air gets to the EGR it has passed the turbo so wont damage that, the most likely cause of smoke is a blocked PCV filter.
Overfuelling causes Black smoke, so The MAF may be faulty, unplug it as a test.
I had both "O" rings blown into the base of the pipe on my car, but it didn't smoke or lose much power...
Give your car a good blast in 3rd gear doing 70 mph to clear out all/any build up of gunge... It's called a Mexican tune up..
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