If you look at it from a cost vs reward stand point; it doesn't change much for performance.
This being said, there are going to be a lot of rebuttals to this. If your TJ is completely stock powertrain wise, you may see a potential gain of 1-2 MPG simply due to a better design in the exhaust flow. Power and torque wise, the measurable difference will be so small. Don't get me wrong, every little bit counts. But too many people purchase aftermarket items like this expecting WAY too much out of it. The 4.0L is designed very well and without power adders; it stays at its optimal range.
If you can find an affordable option, I say do it. Again, we TJ owners can use everything we can get our hands on when it comes to performance. There is also the exhaust note change. Sometimes that makes a fun difference just in the driving experience.
Lots of prior threads and basically two opposite camps on this. Also, most of the offerings out there are junk and will crack eventually. Very few companies offer 304 CRES, 14 ga minimum thickness, welds on both sides, etc.
A forum community dedicated to Jeep Wrangler owners and enthusiasts. Come join the discussion about reviews, performance, trail riding, gear, suspension, tires, classifieds, troubleshooting, maintenance, for all JL, JT, JK, TJ, YJ, and CJ models!