I've been looking to do a straight pipe on my '93 Wrangler YJ. I went to Advance Auto the other day and one of the workers, who suprisingly did a straight pipe on a YJ, came outside and looked at my jeep. He said there was two cats on it and that confused me. For a cat back on jeep would I go from the first cat or the second one? I just dont want toup the back pressure and ruin my engine in some way. By the way I have a 4.0L I6 engine. All help will be appreciated!