Required? No. Worthwhile from a cost perspective? Only you can determine that based on your budget, but with the fairly recently released ability of the HP Tuners MPVI2 to tune the 96+ Jeep 4.0, I believe the "math" behind custom tuning has completely changed.
Previously, only a handful of people had put in the effort to decode the Jeep ECM. If you wanted/needed a truly custom tune, you paid for them to fly to your location, stay in a hotel, plus dyno time. Now, with the Pro upgrade, you can datalog Wideband O2 while driving and just send them the file.
The ECM has the ability to adjust based on the O2 sensor input, modifying its "long term" and "short term" values, but as far as I can gather on the internet, those values are only used during closed loop operation. When in open loop operation, caused by the "acceleration" or "WOT" triggers, by all available information I can find, it appears to just revert to programmed values. This post appears to show info from the FSM detailing the different modes.
https://www.naxja.org/forum/showpost.php?p=245728457&postcount=8
If someone more knowledgeable can show that the ECM does adjust values for "acceleration" and "WOT" modes, then my opinion would probably change, but otherwise, we're not getting the full effect of the modifications we make without changing the tune. If the head porting and roller rockers are the first modification you've made, you may not see a big improvement with custom tuning. If you already have all the other bolt-on improvements, tuning will make a bigger difference. Get into a stroker and it's all but required, IMO... Looking forward to input from people more knowledgeable than I am.
