Darton dry sleeves, a popular solution for racing enthusiasts worldwide, provide another way to significantly increase horsepower rates. The brand also is a good source for customized products for specific vehicles. For instance, Subaru owners can achieve power increases using Darton Sleeves STI components. The engine is a built 2.5ltr genuine Subaru block which has been extensively prepared including CNC close deck, torque plate, darton sleeves, 14mm head studs etc (full specification list available). The heads have had extensive work and have been CNC ported to a custom map, larger valves and bigger camshafts.