leaded fuel will cause the innards of the catalytic converter to melt which will lead to a blockage in the exhaust and eventually not allow the engine to run correctly.
i ran hi-octane (not lead-free) in my surf for 3 years and then i decided to remove the cat as i found that power & fuel economy was dropping. i was right, the cat had started to melt.
if we want to save our catalytic converters we MUST have lead-free fuel in our cars,.. which we dont find everywhere. so you'll have to remove the catalytic converter one day if you want to be able to drive it with peace of mind & fill it from any pump.
i can't justify spending more for lead-free fuel in PK since we don't have emissions laws (which we should) so it's cheaper and more cost-effective to just remove the cat and deal with the (slightly) loder exhaust note (barely audible change).
the correct way to remove it is to have the case cut, remove the innards and have the case rewelded along the cut lines. alternatively people replace the cat with a silencer,... i'm not in favour of this method though.