We are developing ground-based, near-infrared, low-resolution spectrographs that can be used for studying exoplanetary atmospheres. Our current plan is to produce a prototype spectrograph for the Las Campanas Observatory 40-inch Swope telescope, and then a facility spectrograph for the 6.5-meter Magellan telescopes. This pair of projects will study the systematic limitations to achieving high-precision spectrophotometry from the ground including: scintillation noise, instrument scattered light, and variations in subpixel sensitivities. These systematic limitations can be mitigated by a variety of techniques, but perhaps the most promising is the diffuser technology that has already been so powerful for ground-based photometry. In this poster we present the error budgets and instrument design of these instruments, as well as their predicted performance. Our predictions indicate that these spectrographs should achieve less than 100 ppm noise and have just 50% excess noise over the Poisson limit.