I just watched this video as it shows the removal and refit on the down pipe, I removed my engine cover the night before and put plenty of penetrating oil on the four nuts holding the downpipe on as they hadn't been touched in ten years so where tight. I had to use a small breaker bar to get them loose after that just used a normal ratchet.
The clamps on the sleeve that goes over the join between the down pipe and rear exhaust had rusted solid so I cut them off and put a couple of 63mm exhaust clamps from Halfords on there where about a quid each
The top sensor I unclipped and removed it when the pipe was off like in the video as its a lot easier and put it back in once the downpipe was back on, knocking the pre cat out takes about 30 seconds, just keep cleaning it out and tip the pipe out to make sure any doesn't go down pipe into main cat.
