ARP is the world leader in fastener technology. Makers of the finest fasteners in the market, especially for BMW engines, ARP is the choice when you want the highest reliability possible. ARP Con Rod Bolt Sets give you a clear advantage over the OEM Con Rod Bolts: strength! Even cosmetically, the difference in construction and quality is apparent... If you look at many of the OEM bolts, you will see a taper on the threads which actually takes away bolt grip. ARP Pro Series connecting rod bolts are different: Precision CNC-machined to exacting specifications and designed for optimum reliability, their designed for full engagement, quality controlled in each batch, and heat-treated with threads which are rolled to provide up to ten times more fatigue strength than standard OEM BMW fasteners.