think it is 3 bolts attached to manifold
2 bolts attached to downpipe
unplug the lambdas from the loom
put the cat on a suitable surface or perhaps a workbench with a clamp
make sure the downpipe and precat is facing down so when you attack the pre cat bits of metal do not go into the cat and start ripping apart the internals
use a drill and big screw drivers and manipulate it out
do not use lubricants as it will kill the cat
rub down the inside of the downpipe after removal of pre cat to give a nice smooth finish