Timing belt at 63K miles? That is very early, that is a 105K mile item.
So something went wrong where they needed to remove the t-belt anyways (water pump, oil pump, an idler pulley or the tensioner...... or something much worse like head work or shortblock work etc) or the guy was just super anal or something like that, or really wanted to spend unnecessary money.
For any EJ255/EJ257 out there, I'd require a documented compression and leakdown test at the absolute minimum, by an independent source (not the seller). Then there are lots of other common things on these cars.... control arm bushings, clutch bearings, radiators, stock TMIC, then there's the turbo....
Do some searching and browsing and you will find a ton.