I flipped my ball joints about a year ago. It is a great mod if you need the extra articulation for crawling. I did not use any spacers when I did mine. As your front A-arms drop, your CV joint angles increase, and at some pointyour CV joints can actually absorb as much torque as it is transmitting, causing premature CV breakage as well as torn CV boots. I don't want to scare you away from using the spacers if you need them, just be aware of some of the possible consequences. BTW, you can get much of the same effect by modifying your front droop stops. Then when you crank the torsion bars, your ball joint flip will straighten out your upper control arm geometry to a position that is closer to the stock position.

Andy