  Let $M$ be a smooth closed orientable surface. A Gaussian thermostat on $M$
can be seen as the geodesic flow of a certain metric connection with torsion.
These flows may not preserve any smooth volume form. We prove that if two
Gaussian thermostats on $M$ with negative thermostat curvature are related by a
smooth orbit equivalence isotopic to the identity, then the two background
metrics are conformally equivalent via a smooth diffeomorphism of $M$ isotopic
to the identity. We also give a relationship between the thermostat forms
themselves. Finally, we prove the same result for Anosov magnetic flows.
