Hi, I have a 97 4x4 club cab, 5 speed. I found a "cat back" 4" exhaust on Craigslist for $50.00. I'm trying to determine if the stock downpipe is worth the cost to replace (seems it's about 75-125) also. I believe it's 3.5" from the turbo down to the bend under the passenger seat (correct?). The truck is stock (and will stay stock) except for BHAF. I'm looking to make the motor exhale better, but not sure that the difference in the downpipe will be worth the cost. I occasionally haul a trailer (4.5 to 9 k) but the motor never gets hot, nor do I push it. What do you think? I'm also making the "cat " either go away or be just a hollow shell. I would appreciate input please....Thanks,paul