Joined: Apr 2008
Location: San Fernando Valley
It can't hurt. The panhard bar will allow you to center your rear axle; it might be off center a little after lowering. But it'll drive fine without a panhard bar, no frog-hopping. I put Eibach springs on my last two GTs, but no panhard bar on either. My rear axle did shift a little to the left. Now and then, I think about getting a panhard bar; meanwhile, the left side of my car looks a little bit better than the right.
1972 Mach1(351C), 2004 GT, 2007 GT, 2011 GT (Magnacharged), 2017 GT350