I like my 2.5. It does everything I need it for except go fast.

 

Do you want a Cookie LOL! Think of it this way, if you have front tow hooks and a Samurai in front of you, you can go places that the I6 will never make it. I do not have an issue with my 1.6L there have been times it would have been nice to have more power, but 99.9% of the time I will take gear over power. If you do a few things to your truck it will do both on and off road for you and you will save money on the fuel the I6 is burning.

 

First time I saw little Suzukis buzzing around was many moons ago in Barbados.
Always liked them ever since.

 

well if he's got 4.56 gears in it then he's got to either replace the axles, or go with more power. theres a few things to do the 2.5L to get a bit of extra power, 4.0L throttle body is a real easy one... Electric Fan, better plugs and wires, high flowing exhaust and intake systems... but then you end up pumping money into it then might still end up doing a swap.

also if you've got 4.10's going to 4:56 would help put the torque where you need it... and would only be increased with the 4.0L it will help ------ around extra torque all around where you need it.

 

If he has 4.10's he can go as large as 4.88's unless TJ's have changes to the carriers I am not aware of. Not sure what is available, but there may be other power robbers like water pumps that can be replaced by electric as well.You can try indexing your spark plugs as well so that you get a better burn of the fuel. It has been a while since I did anything with a Jeep, but have they not started making gear sets for the cases yet, that would help a lot.