Can use some Thermostat and Rad Cap advice

If you're not drag racing there's no reason to have a 160° thermostat. A 180° or even the stock 195° will work just fine for your application. You say it idles at 200°, so guess what? It will still idle at 200° with a 160° thermostat.

Your engine tune will be different at 160° than 200°, if you're street driving the car you're better off tuning the engine for what the temperature will be most of the time. If it's not tuned to run at 160°, on cold days when the cooling system can keep it at 160° it'll always act like it's running cold. Because it is.