The high pinion is about 30% stronger and has more drive shaft ground clearance.

 

IMO get the 99. The D35 far outweighs the 8.25 with an 0331 head and coil packs.

 

I researched this for about 6 mo. before buying and found the 99 to be about the best year. One thing many of them like mine came with the C 8.25 and the HP D30. The head was a much better flowing one than the previous years and many upgrade to them for that reason. My 4.0 has 240,000 on it and never been touched and runs very well.

I went on many XJ and Jeep sites it seemed that the 2000-01 were the 2 years to avoid the engines were different than even the 99 as were they but not the problems.

IMHO a 97-99 would be my choice working from the top down "99" the 1st.