33's are terrible with stock gears nevermind 35's or 36's

 

You will for sure have to regear, my XJ has 3.55 gears under it, with 235/75 tires it'd run like a scalded dog, put the 35"s on it and its hell, on flat ground it keeps up with traffic and so forth easy, but i live where there are mountains so the two times ive drove it off the mountain and back, coming up it turns a good 3k just to stay at 55 mph. Not good. Drinks the gas and is hard on it. Either way 33" or 35"s you are gonna have to reargear, i say keep the 35" and do a hair extra trimming.. I trimmed mine way before i got the 35"s and there is plenty enough room in the back for them. The fronts though, i had to retrim but only cut out with width of the 3M tape, no rubbing the fenders at all now.

Heres a pic of how much room i have with trimmed rear fenders and 35"s... Plenty enough...