No, it could actually decrease fuel economy by decreasing the oil viscosity.
yes if you live in a cold area it could help, example, a 160 degree thermostat will open before a 180 degree thermostat, thus letting the warm coolant from the block to circulate thru the radiator and heater core, thus giving you warm air for your heater faster than a higher rated thermostat
Honeywell
Rated R
Mass Effect 2 is rated M for mature by the ESRB.
Economy - 1917 is rated/received certificates of: UK:U
ADB
check to be sure that the thermostat is not backwards and is the correct heat rated unit for the car
Locate the lower hose pipe from the radiator to the engine block. The thermostat is within the housing that that the lower pipe is attached to at the engine block. The housing can be removed ( with the hose pipe still attached) by removing the two 10mm bolts. The thermostat is then exposed and can be removed by lifting it out. The only thing holding in place is the rubber sealing ring, which you should be careful not to damage on removal. Subaru thermostats are rated to open at 76 degrees centigrade, but usually don't open till 90 degrees are reached. If you have a 90 degree opening thermostat, then you can overcome the overheating problem by drilling 3 or more holes in the face of the thermostat, being careful not to drill into the 'spring'. Frank Sheehan, Dublin, Ireland
Using an octane rated lower than your vehicle specification will damage the engine. I would recommend not doing that.
Mother Economy - 2007 V is rated/received certificates of: Israel:16
Mass Effect 2 is rated M for mature by the ESRB.
Batteries are rated as ampere/hour any circuit that draws power from it effects it. The lower the internal resistance of the circuit the shorter the useful battery life as discharged.