Hi Guys, my 05 V has 141,000 miles on it and about 4,000 miles back the check engine light came on. I am told that it is the cat on bank 1, not blocked but failing. My question is, which side is bank 1? Also, one of the bolts that hold the exhaust to the the flange on the cat (drivers side) is cross threaded and leaking a bit ( my fault, just haven't had time to fix it) even though that is after the cat and sensors could that possibly be causing a false reading? Last question, what are you guys using to replace the cats when needed? Any good aftermarket stuff out there? Thx in advance.