Ha ha, what a load of tripe that is. There's a guy recommending not to use ULP to wash parts - by inference leaded petrol is better...?
Because TEL is an organic compound, it can be absorbed directly through the skin which is one good way of increasing your body's exposure to Pb. So leaded fuel is definitely out for washing parts, not that you should be using petrol for this anyway.
I don't like handling it that much when doing fuel drains etc as AVGAS has a pretty high concentration of it compared to normal old leaded MOGAS.
As far as catalytic converters go, they have done more for improving air quality than people will ever imagine. You only have to take a visit to places like India and China to figure that one out.
People who remove them from their cars mostly do it out of ignorance in a misguided attempt to get the last 0.4% of power that they will never use anyway, except as an irresponsible loon at the traffic lights.
A