Thanks for the info
One thing I forgot to mention is that I had to take the car for a yearly emissions test (required by law) and it passed with low emissions. Lambda value on emissions test was 1.0, CO and HC values were low - this was even before the blocked (left) cat converter was replaced
But then again, maybe the tester put the emissions testing probe up the right exhaust (good side) not the left one (faulty side), I don't think they test both tailpipes on V-engines...