I'm in the VERY begining stages of a SAS information gathering. Given the multitude of parts available for the Dana 30 axle it seems a prospect for a swap. ZJ's & XJ's regularly run 33" tires with no problems with the D30. It's also high pinion, on the correct side, and upgradable to 29 splines and various lockers and manual hubs.You can get the D30 geared down to 4:56 or 4:88. Question is...is 4:56 too far away from the Xterras 4:636? I know it sounds goofy but i've heard of some 4x4's that have slightly differant ratios front & rear. I'd definatley like to keep the X rear diff.