  A Tully-Fisher (TF) relation from H-alpha rotation curves of 19 luminous,
star-forming galaxies reveals there is little evidence for evolution in the
mass-to-light ratio (M/L) of these galaxies to z~0.3. The near-infrared Tolman
surface-brightness test for other luminous galaxies indicates their luminosity
also is little changed to z~0.3. In this redshift regime, internal velocity --
luminosity relations like Tully-Fisher may provide a way to measure q0.
Discrepant results from several intermediate redshift Tully-Fisher surveys,
however, must be understood first. One possibility is that different surveys
sample different galaxy types and TF relations. Alternatively, M/L of some
spiral galaxies may evolve rapidly with look-back time. Larger surveys are
needed to resolve this issue. A different approach is to determine disk and
halo M/L separately. Such measurements, even at low redshift, would be
sensitive to the star formation histories of disks. We outline plans for
lambda/dlambda ~ 10000 integral-field spectroscopy of relatively face-on
spirals using the 9m Hobby-Eberly Telescope. Rotation curves and disk stellar
velocity dispersions can provide statistical information about the M/L of dark
halos as well as luminous disks.
