They are also specifically made for the Z32 as it has an extra offset so the securing perches do not get damaged by regular suspension travel. The original style Midori/TBO arm was designed for and R32 Skyline. This offset is essential for proper suspension travel especially under extreme and track conditions. Even the stock A arm has this "dimple" or clearance built in to its design for regular suspension travel. Without this offset, the adjusting collars can be damaged causing total failure of the arms. The Powertrix Control Arms are made of heat tempered forged steel. There are inferior copies made of aluminum that are not as strong and are prone to bend and flex. These suspension components under go massive stress and entire weight transfer of the vehicle. A daily driven or street car is subjected to even more blunt or shock force due to street hazards and road conditions there fore we do not recommend the use of aluminum for these components. These allow for camber adjustment up to +/- 4 degrees.