BY REFERENCE FERREA - Reinforced spring cups 

Titanium halves retainer mass at equal stiffness, which takes weight straight off the fastest moving part of the spring stack. Two Ferrea part numbers are active here, both listed for the 2.8 litre 24-valve VR6 fitted by Volkswagen and Seat, engines AQP, AUE, BDE, BDF, AYL and AXK in the Golf IV, Bora, Jetta IV, Sharan, Leon Cupra and Alhambra. The first, E11063, is the titanium retainer on its own, for replacing one piece or completing a set. The second pairs that same retainer with the Ferrea S10087 spring as a matched assembly: the sensible choice when the head is off and springs and retainers are being renewed together.