How much horsepower can a standard clutch (and gearbox too I guess) on a Fiat Punto Evo Sporting (1.4 turbo multiair) 2011 take safely?

Thanks!

All that the standard engine can produce, plus a little more. Margin will be big enough that it does not slip too early as it wears, but no more than absolutely necessary. Higher torque capacity is gained by a larger diameter, or heavier springs, giving a heavier pedal.

If looking to increase engine power, look at the maximum output of that engine in any Fiat, and see if its clutch is compatible with your flywheel/gearbox. Also consider diesel variants, as they produce more torque, so have heavier clutches. Don't assume gearbox input shaft is the same petrol/diesel, so might have to go diesel gearbox, so care with ratios needed too.

Only people who know the capacity of the clutch will be Fiat and the OE clutch manufacturers, and they won't be telling.