I was trying to google for the above information without luck - do you have any links where I could read about the 2 catalytic converters in RX400h?
EDIT: actually, after looking found the two other catalysts in the engine manifold diagram - from https://lexus-europe.epc-data.com/rx400h/mhu38r/5163/engine/1701/?full
Still, would love to have some source for the 15% bit of emissions work.
If the 15% bit is true, this brings me to the reasoning that I can skip replacing the stolen cat.converter avoiding the risk of repeated theft - at least for now or until the wave of thefts reduces.
I have already ordered the 3rd-party one from Catman.co.uk, but thinking I will not fit it and will wait for the MOT and try passing MOT without it. If they fail it - then I'll fit it up for £30 pounds or so.
For now a simple pipe will do.