Computer wont go into "closed loop" until engine temp is X amount.A cooler thermostat will take longer for an engine to heat up.Wasting fuel,causing excessive cylinder washdown,and shortening cat con life.
Yes, issues with colder thermostats.
Get a Stant at NAPA, etc.
Make sure the Temp needle is at least 2 needle widths above the 1/4 mark. If not, change your ECTS (Engine Coolant Temp Sensor) as they are well known to get cracked, especially the old polymer one.
Two Saturn musts: A Stant thermostat + a new ECTS.
Get the hottest one you can, 195 it should be. The rubber tip is a wear item that leads to bypassing and cold performance after a couple years; get something with a good warranty and you're golden, save for the labor.
I recall reading some saturn's (all?) having head, headgasket, etc. problems...I'd go with an OEM...or a SuperStat from STANT if there is one available.
Check rockauto.com they usually have a good list of products available....
185 is honestly fine... I ran a 185 in my SL1 and it was good. The OEM stat had been running too cold for a long time and with the new one, the gauge read 3/8 (proper for 96 and up) and had good heat, with a dealer 185 thermostat. You are worrying too much, just get a good one and replace it.