<strong>1.</strong>The lower control arms are made from boxed chromoly plate and feature internal gussets to create extra strength and durability. The upper control arms are made using chromoly tubing. While JD offers the upper control arms with fittings for the factory Toyota torsion bar system, JD Fabrication recommends converting to coilovers instead. Why? The cost of upgraded torsion bar components combined with the added cost of making more intricate upper control arms places the total cost quite close to that of converting to coilover shocks.