With the Mk1 Sporting it's a tale of two engines.
Up to 97 there was the old 1.6 litre unit which gave 90bhp which many would consider a proper size engine for a 'warm' hatch.
But if I were going to get a mk1 sporting, I'd get a later one (97-99), budget permitting, with the 1.2 16v engine. It's down to 85bhp *but* because it weighs a lot less than the old 1.6 unit it actually gets to 60 a smidgeon faster. A lighter car, especially at the front end in a front-drive car means better handling and less understeer if you push it. It's also a more fuel-efficient engine (41 rather than 35 on the combined cycle, probably as much as 7-8mpg difference round town at times) and will feel a bit sportier because it's a 16v engine. Mind you there's a lot more to the 8v/16v difference than that but I won't go on.
With any Sporting it's important to make sure it hasn't been thrashed by a would-be Schumacher. Insist on a test drive, make sure it starts OK, check the oil, all the usuals. As with all Puntos I'd try the electrics on full blast to make sure nothing is flagging. When it's warmed up, rev it slowly up to peak for a while to make sure there's no black smoke from the exhaust. Check for mayonaisse as well to make sure the car hasn't spent it's life doing 2-mile journeys, the usual small-car check stuff.
If the car's done over 50,000 miles really check the gearbox. If there's what might be a noise, push the clutch down and listen. If it disappears, then comes back when you let the clutch up the gearbox bearings might be on the way out. According to Parkers, this is the second most common problem on Puntos after ignistion coil failure.
Again, as with all Puntos, check the bodywork meticulously. Look for crash damage - evidence of respray and stone chips. Punto has high sided-doors and they dent easily: run your eye line along the door in the sun and look for small dents all along. I got £100 off my Punto for spotting one of those
I think I should sum up

If possible, get a later 1.2, make sure it's not been razzed, look for service history, do usual Punto checks. Good luck!
Spirito di Punto | M-reg 55SX, black, 5dr.