Hi,
Please learn to give useful informatins.
--> we can not know what this means: is it 1cm x 1cm x 1cm or is it 1m x 1m x 1m...
That´s not the problem of an autotransformer.
In your case the 160VA autotransformer is as small as an 100W standard transformer.
They have all form options than a standard transformer: toroidal, or standard, it may be PCB mount or not, potted or not... and so on.
If an autotransformer is too big, then every low frequency transformer will be too big.
Review the thread to see how many other options you have to generate 80V/2A AC from 230V AC. I see none.
I doubt that repeatedly asking the same question will bring new results. (More than 440 times this thread has been viewed)
I doubt that repeatedly refusing facts or posting unverified statements will bring you a step ahead.
Honestly, I gave the best (smallest) possible solution that I know.
Klaus