If I currently have 4.10 will I have to re-gear for a 3.5" lift and 35" tires? Or any other modifications that I may have to make?

 

How much time did you spend searching before you posted?

 

Depends on which engine you have, manual or auto transmission and are you looking for greater off road performance or want the revs a little lower for highway speeds. Lots to think about because you want to be happy with it after dropping around $1500.

 

You don't have to but the Jeep will be really slow.

You should but you don't have to.