I own a 1995 C280 and it has had the cat of since May 7. In its place, I ran an stainless steel pipe. I've only put about 2000 miles on the car w/o the cat. I know the car is OBD I, but is there anything I need to know before I put the cat back in. The cat has been collecting dust in the garage ever since. Are there any precaution I need to to be aware of before welding it back in or having my mechanic do it for me?