  Angle-dependent magnetoresistance measurements are used to determine the
isotropic and anisotropic components of the transport scattering rate in
overdoped Tl$_2$Ba$_2$CuO$_{6+\delta}$ for a range of $T_c$ values between 15K
and 35K. The size of the anisotropic scattering term is found to scale linearly
with $T_c$, establishing a link between the superconducting and normal state
physics. Comparison with results from angle resolved photoemission spectroscopy
indicates that the transport and quasiparticle lifetimes are distinct.
