I have quite a lot of experience solving unsteady Euler equations, including multi-component ones, with in house-coded finite-difference and finite-volume methods, including MacCormack and MUSCLE schemes and WENO flux reconstruction. Now I'm considering "upgrading" to laminar NS equations for compressible gases (i.e. without any turbulence model).
Is it generally considered a hard switch? What are the most complex parts to understand/implement regarding the difference between Euler and NS equations?
What would be the simplest way to incorporate viscosity in FV formulation? Same question with FD formulation.
What would be the simplest way to incorporate diffusion and heat conductivity?
In general, I'm looking for some good detailed literature/tutorials for NS equations similar to LeVeque's books (which are only for Euler equations, as far as I know).
EDIT: added info about compressible equations and comment on "laminar" term as Spencer Bryngelson suggested in comment.