In this talk, we present two subcell limiting strategies for stabilized continuous Galerkin spectral element methods (CGSEM) applied to compressible flow problems, targeting robust shock capturing and positivity preservation. Both approaches are based on split-form CGSEM discretizations of the compressible Euler and Navier--Stokes equations (employing a two-point flux implementation [1]) stabilized with local projection stabilization (LPS) techniques. The first strategy directly exploits the two-point flux formulation of the split-form CGSEM discretization of the advective fluxes. Dissipation is locally introduced at the level of each two-point flux evaluation, allowing non-oscillatory shock capturing to be achieved. By carefully designing these localized dissipation terms, the method preserves high-order accuracy in smooth regions while effectively controlling spurious oscillations near discontinuities. The second strategy extends subcell limiting techniques originally developed for discontinuous Galerkin spectral element methods (DGSEM) [2] to the continuous Galerkin setting. We show that the split-form CGSEM discretization can also be recast in a flux-differencing form, enabling the construction of a compatible low-order subcell finite volume method. This low-order scheme is combined with the high-order CGSEM at the nodal level to efficiently handle strong shocks while directly enforcing physical bounds on quantities such as density, pressure, and entropy. Both strategies are implemented in the three-dimensional, GPU-accelerated spectral element code SOD2D [3]. Numerical results demonstrate their robustness, accuracy, and efficiency for challenging compressible flow problems on curvilinear meshes. References: [1] Gassner, G. J., Winters, A. R., & Kopriva, D. A. (2016). Split form nodal discontinuous Galerkin schemes with summation-by-parts property for the compressible Euler equations. Journal of Computational Physics, 327, 39-66. [2] Rueda-Ramírez, A. M., Pazner, W., & Gassner, G. J. (2022). Subcell limiting strategies for discontinuous Galerkin spectral element methods. Computers & Fluids, 247, 105627. [3] Gasparino, L., Spiga, F., & Lehmkuhl, O. (2024). SOD2D: A GPU-enabled spectral finite elements method for compressible scale-resolving simulations. Computer Physics Communications, 297, 109067.