Good valid points there from the expert A series turbo man himself!
There are plenty of T25/28 versions out there with much bigger AR
on both sides than an A14 would be happy on the street.
Id definitely go for one of the twin turbo snails as mentioned &
if affordable the gt22 are perhaps the most efficient non BB snails.
Like all good turbo set ups the devils in the tuning so best get it
on a dyno with good hands once its mostly setup.

I often get a lift in a GTI 1300cc with a gt2252 and that thing is
just bananas on how well it destroys the bitumen from any rpm.