You'll gather by the trivial nature of the problems listed so far that not a lot goes wrong with the t-jet; it seems to be just about the most reliable of the grande puntos but there are a couple of things to look out for.
As with all puntos the brake servo mounting plate is prone to rust, its a cheap part but an awkward job to replace.
The 5speed gearbox will probably crunch when selecting reverse, this is normal as there is no synchromesh (select 1st before reverse to avoid crunch).
Diffs can give trouble on seriously lowered cars but I've not read of and going on standard cars.
As with all grandes rear wheel bearings go early but this is a cheap and easy fix.
The turbos seem to last well but evidence of regular oil changes is always good on a turbo car.
The 5speed t-jet gearbox doesn't suffer the bearing wear problems that affect the 6speed grandes.