zgb, yes a hybrid 17/20 is a vnt-17 hot side with a vnt-20 cold side.
or maybe some use the 17 housing machined to fit a 20 compressor wheel but that's too much restrictive to me,,,
micky, sorry, I still don't believe it, the big hp guys always use bigger stuff.
I can remember tdisportR's 110
ibiza that had an unidentified turbo that accordin to paulo was 'much bigger' than a 20. But then I'm talking non-pd so maybe the pd's can get more hp with smaller turbos,,, I don't know.