With regards to performance, prerequisite and setup.
About 40 amps I'd say . You can get the same machine in two different amperage and the only difference will be the thickness of material it will cope with.
Or about 1 mm. The bottom end may be of more interest than the top.
and the tickness of the mig wire at 160 you can go 0. to 0.8 with 200 amps you can use 1.0 wire. Another thing is the fuse on you instalation 160 a 16a will suffice on a 200 amp a 25a is recomended.
Duty cycle too.
~100A flat out all day for the 160, ~150A for the 200.
It'll vary lots manufacturer to manufacturer and my estimates might be a out but you get the idea
Separate names with a comma.