I must have mis-understood you about the heat shield. I would have to say that is most likely the ball joint. The mods that you have wouldn't have anything to do with the ball joint going bad. If your dealer doesn't want to cover it then I would check around, because they should do it with no probs.

Jen- usually the CV's only make noise when you turn. What were you told was cracked, the housing? If you have a cracked CV I would get it replaced ASAP. A CV can come apart at anytime and this is not a pretty site. Best case scenario is it happens at home and you get it fixed pretty easy. Worse case scenario, well just imagine you driving down the highway at about 80 and your front axle decides to drop out. Not a good thing.
Joe
97 GS w/ Hahn stage 2
Keep cruisin' & keep the shiny side up.
http://joeseclipse.homestead.com

Yeah I got two tens in the back...two ten pound bottles!!!!

Joe
97 GS w/ HRC stage 2 +