I nuked the cat on both the '01 and the '02, and waited to see how long before they tripped a SES light before turning off reporting via HP Tuners... The '02 went 2+ months, and after a pully swap and headers I had to retune obviously, so I turned it off... The '01 set the code in less than 3 miles after swapping to a catless DP. Beats the hell outta me.