He will need the hubs (there are some used GTI or S3 ones frequently)
and new 55 mm struts/dampers.
But this is a question of the money he's willing to spend.
On a 280 mm front setup I'd just go for some AP Xtreme discs and
Ferodo DS Performance pads.
From what I know the tiny 256 mm setup isn't easy to upgrade on
the 280 mm. Same caliper as 280 mm, but no carriers to change.