Dynamically cold stellar streams from globular cluster progenitors are important probes of the Milky Way’s dark matter; their kinematic heating, for example, could help constrain the physical properties of dark matter subhalos. Direct N-body simulations are considered the ground truth, but are often an impractical choice due to the computational expense. Particle-spray methods successfully produce stream models very quickly, but are reliant on making certain approximations about escape physics. We have bridged the gap between these approaches with KRIOS, a new basis-expansion N-body code. In this talk, I will provide a high-level review of KRIOS’ technical details, discuss preliminary results on streams from spinning progenitors, and address the potential complementarity between KRIOS and the particle-spray distribution function developed here in Ann Arbor.