When I bought my '97 ZJ, there was only one thing that bothered me. The performance was a little less than I had expected for a 5.2 V8. I took it to my exhaust guy to have it tested. After doing a AET test, he replaced the old worn out cat with a high performance one, keeping everything else intact. I asked about changing the intake, but he said to test one change at a time. So nothing else was touched. Not the muffler, pipes, or anything. Upon start-up you could hear a difference. A little more throaty, even at idle. Driving home I was impressed. I would've thought more had been done if I hadn't been there. On older vehicles i've added headers and changed carb jets without feeling this much of a difference. Amazing! KEEP THE CAT!