My suggestion is if the wheel bearings are properly spaced or tensioned. I've had wheel bearings that were worn, shot or loose cause problems. Any Indy mechanics in the area? I've had some of my cars in various places for alignment and they did the alignment, but didn't look at what parts were worn. One guy I take mine to has caught a few things. Also, just thinking, but check the shocks or struts. I've had some stick or go bad. Causes problems. I've hear to have the car aligned after changing shocks or struts.
Tom