High-pressure fluid jet systems are provided which include a pump to selectively provide a source of high-pressure fluid, a cutting head assembly configured to receive the high-pressure fluid and generate a high-pressure fluid jet for processing workpieces or work surfaces, and a fluid distribution system in fluid communication with the pump and the cutting head assembly to route the high-pressure fluid from the pump to the cutting head assembly. The pump, the cutting head assembly and/or the fluid distribution system include at least one fluid distribution component having a unitary body formed from an additive manufacturing or casting process with an internal passage having at least a curvilinear portion to efficiently route matter through the fluid jet system. Example fluid distribution components include fittings, valve bodies, cutting head bodies and nozzles of the high-pressure fluid jet systems.