Get your head around the need for upper control arms.
Upper control arms are a bit harder to get your head around than a diff drop, because they are basically a wheel alignment device product that brings back camber and caster which is sent off kilter when performing a high lift on long-travel suspension.
All you need to know about why you need upper control arms.
Vehicle makers decree a wheel alignment specification for a number of reasons... tyre wear, return to centre steering, tracking, high-speed stability - it's all about geometry. Decent upper control arms used as a bolt-in the system will give you some massive returns on your investment.