"When a catalytic converter fails, it blocks completely and in effect, instantaneously -a complete blockage of the flow of exhaust gasses. This leads to a reverse-flow pressure pulse back through the exhaust system to the turbochargers, causing damage."
Sounds like riceburner folklore to me. Surely if the gas path becomes blocked the turbo will just stop, since it is driven by the gas flow.
"I regret I am unable to provide supporting documentation. What I have written here is as it was explained to me by the engineer that does such a superb job of looking after my car... as he should; I pay him enough! I have no reason to disbelieve a man of his experience -he's been looking after my car for the last 11 years, and I was aware of him by reputation before that as the man to go to with 'performance' vehicles for many years prior. In this, as in other things beyond my personal experience, I take the word of the professional I am paying to do the job before I trust the anecdotal evidence 'heard on the street', as it were."
License to print money by perpetuating a myth among users who don't know any better.
"In another example, the Chief Engineer of the organisation that looked after my aircraft used to (he's dead just now -cancer, not hooning) "
Doesn't the removal of the catalytic converter leave you with a carcinogenic exhaust if burning unleaded petrol? Maybe he'd have lived longer if he had a better engineer looking after his car.
http://www.maltatoday.com.mt/2001/1209/t3.html