You would have to be careful. Most people buying cheap kits get the same stabilizers that everyone uses in every high end build, its like a $20 upgrade. They also clip the stabilizers, make sure they are lubed properly, and some people put pieces of cloth band-aids under them to soften impacts and make it more quiet. Some people also lube switches which is a little harder to do right and takes some tools.
If you wanted to test, it should be on equal footing. A $200 keyboard with the same switches and modifications as a $2000 keyboard. Same keycaps as well.
If we're talking kits, honestly you might even want to use the same board and just have the case be different.
Even with all that, there's a good chance they will be able to tell that the keyboards are different, simply because the acoustics of the cases are going to be different. They just won't be able to subjectively measure the quality.
$200 might be too low though, I think the realm of it not being noticeable is probably closer to $300-400+.
If you wanted to test, it should be on equal footing. A $200 keyboard with the same switches and modifications as a $2000 keyboard. Same keycaps as well.
If we're talking kits, honestly you might even want to use the same board and just have the case be different.
Even with all that, there's a good chance they will be able to tell that the keyboards are different, simply because the acoustics of the cases are going to be different. They just won't be able to subjectively measure the quality.
$200 might be too low though, I think the realm of it not being noticeable is probably closer to $300-400+.