We contend that carbon fiber reinforced silicon carbide material (C/SiC), developed by IABG, represents the state- of-the-art for ultra-lightweight, high precision optomechanical structures that must operate in adverse environments and over wide ranges of temperature. C/SiC employs conventional NC machining/milling equipment to rapidly fabricate near-net shape parts, providing substantial schedule, cost, and risk savings for high precision components. Unlike power based SiC ceramics, C/SiC does not experience significant shrinkage during processing, nor does it suffer from incomplete densification. By modifying certain process steps, the thermal and mechanical properties of C/SiC are tunable in certain ranges. This paper focuses on recent advances in C/SiC technology and application of this technology to high precision, lightweight applications such as meter-class optics and optical mounts. We also introduce a design for new, high precision mounts based upon standard optical grade C/SiC (formulation A-3) and a custom formulation of C/SiC (D-4) which was engineered for Schafer Corporation by IABG. The A- 3 and D-4 formulations have a near-perfect CTE match with silicon, making them the ideal material to athermally support ultra-lightweight silicon optics that will operate in a cryogenic environment.