The 180F t'stat will work just fine - I've experimented with 170F, 180F and 192F. Currently run a 180F. Just don't put it in if you have an overheating problem you're trying to solve.
The 160 should work fine with efi -- the car goes into closed loop just as soon as the O2's come alive (seconds with heated sensors, a minute or two with unheated) and the computer will "learn" about the lower operating temp over time and adjust the mixture so it's not too rich.
But there's no reason to go down there. Engine wear is increased, and for no benefit. Ideal -- intake air as cold as you can get it -- the colder the better; coolant temps - 180F-200F is fine; oil temps between 210F and 230F. That will net you the best compromise of performance, oil and engine longevity.