Standard exchange: You send us a clean cylinder head in good condition with less than 50,000 km or we transform yoursStage 1 = Micro-blasting, polishing of the ducts, modification and lapping of the valve seats and guides (price displayed)Stage 2 = Stage 1 + larger valves + reinforced springsStage 3 = Stage 2 + lightened buckets NNOTE: Original parts to be replaced not included