Don’t say put them outside

So since I’ve had the car 2 years when I plant the loud pedal with the windows open over 4000rpm after a while the cats stink. I had cheap aftermarket cats on and blamed this and so I decided I hated the stink and now have genuine cats on there…. Problem is these still stink… granted not as much but they still do? I will add I have lpg but since my filling station is not in use it barely gets used unless I happen to pass one… and I had it converted it’s stank since before this…

Is this just a thing of the 4.2s? I have no lights or faults?

Any idea? Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

No smelly cats here , so probably not a 4.2 thing 4.4 AdBlu Tractor Stolen
4.2 SC - sold

No smelly cats here , so probably not a 4.2 thing

+1

It MAY not be the cats or does t smell like rotten eggs in my opinion it smells more like a racing car … I can’t explain it better than that 😂 Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

if it smells like rotten eggs:-

"The smell of rotten eggs is due to a compound called hydrogen sulfide. This comes from the small amount of sulfur that is present in the fuel. ... Two other causes of rotten eggs besides a broken catalytic converter include an engine that is running too hot or a broken fuel pressure regulator"