  We present results on the thermal and kinetic Sunyaev-Zel'dovich (SZ) effects
from a sequence of high resolution hydrodynamic simulations of structure
formation, including cooling, feedback and metal injection. These simulations
represent a self-consistent thermal model which incorporates ideas from the
`pre-heating' scenario while preserving good agreement with the low density IGM
at z~3 probed by the Ly-a forest. Four simulations were performed, at two
different resolutions with and without radiative effects and star formation.
The long-wavelength modes in each simulation were the same, so that we can
compare the results on an object by object basis. We demonstrate that our
simulations are converged to the sub-arcminute level. The effect of the
additional physics is to suppress the mean Comptonization parameter by 20% and
to suppress the angular power spectrum of fluctuations by just under a factor
of two in this model while leaving the source counts and properties relatively
unchanged. We quantify how non-Gaussianity in the SZ maps increases the sample
variance over the standard result for Gaussian fluctuations. We identify a
large scatter in the Y-M relation which will be important in searches for
clusters using the SZ effect(s).
