Eventually the bushings could warp and expand the area around them, meaning if you tried to replace them the new bushings wouldn't fit properly, so there would be TONS of play. Also the bearings reduce friction, which alows the moving parts to move more freely and faster. They also reduce wear on moving parts since they reduce the resistance it takes to move those parts.

My bushings are stock, and they show no signs of wear and/or tear, esp. because I put in plenty of cooking oil/spray in them.

having the bearing upgrade, i noticed a better drive.

ight thanks

yah mine in the rear have worn down to the point that some of my gears grind :(

IMHO, the bushings have way too much slop out of the box

no. your xmod will just be slower. eventually the bushings will wear to the point that they have to be replaced because of the excessive slop. i'm near that point with my F150 that i've used somewhat heavily on and off for about 4 months. the bearings probably will far outlast your xmod.