From Experince with my 97 TJ i drove around on 35s for 1 1/2 years or so with the stock 4.10 gears, it wont hurt anything just may not get out of 3rd gear much. Just drive smart and know its not a race car. Also if it is a stock d35 with 4.10s in it you will not have to get a new carrier. With those 4.88s that thing will be a beast offroad but the highway still sucks. The gears and an efan are going to be the most noticable in power or lack there of. Just make sure who ever does the gears knows what they are doing because if done wrong you in a whole other set of probs. Just my .02