I failed the TX emissions test for NOx by about twice the limit. Having owned the car for about 4 years and not knowing the age of the cat, I decided to go ahead and replace it since it was the most likely cause. Co and HC levels were well within acceptable limits. After reading the board and doing some checking around, I decided on a cat manufactured by DEC. After receiving the cat, I was very impressed with the quality of construction. This model has the cat with the long pipe attached. Tubing bends and welds were well made. Installation was a perfect fit. I would highly recommend this brand to anyone needing to replace a cat. I feel very confident that I will pass the emissions test, since upon inspecting the old cat found that someone along the way had completely gutted the internals. It is amazing that I did not fail the test by larger numbers. Car runs alot quieter now that I don't have that expansion chamber in the system.