This is utter hogwash. Yes, the FMJ and B/R body spindles are taller. But the change in geometry is almost negligible, and arguably an improvement. Ehrenberg gave traction to that whole idea with his disc-o-tech article, but apparently he didn't bother to actually check the geometry numbers. This article actually checked the geometry, and explains why it's no big deal to use the FMJ spindles. I run them on my Duster, even though it came with A-body spindles, exactly because of the improvement in geometry for wider tires explained in the article.
Swapping Disc-Brake Spindles - Mopar Muscle Magazine
