IMO, I'm not really a big fan of 160 stats, unless you live in the Sahara region, or you're running a serious engine setup w/ an underdriven water pump. I would recommend a 180 stat to anyone, but that's just me.
On the street if your cooling system is working 100% correctaly you will never need anything cooler than the stock thermostat.
A cooler thermostat WILL NOT compensate for a cooling system that is not working properly.
Look else where to fix your overheating problems.
Auto Zone no longer stocks Robert Shaw Thermostats. You can special order the 160 Hypertech Power Stat from them for $9.99 or get an Auto Zone brand 160 T-stat for $3.99. The part number for the Auto Zone T-Stat is 400-160. It works just fine, if you do the pin 14 fan mod. Mine stays just shy of the N on the temp gauge in town.