SPL Parts Rear Upper Control Arms 2014+ BMW M2/M3/M4 (F8X)BMW F8X adjustable Rear Upper Arms (RUA) are an absolute necessity to maintain proper rear camber and reduce tire wear on the street and track. The stock BMW setup has an aggressive camber curve through bump travel, which is very apparent on lowered cars. Excess negative camber causes premature tire wear on the inside edge, and reduced traction on acceleration while too little camber will limit rear grip while cornering. Our Rear Upper Arms provide a