Hi! Here's a video which shows the difference between Fiat Punto HGT 1.8 16V and Alfa 1.8 TS camshafts. On intake camshaft the difference isn't huge but check out the exhaust!
From the specs of the cams, Fiat fitted the camshafts from the 1.6TS to the 1.8 HGT, the 1.8 & 2.0 camshafts are the same spec & a nice cheap upgrade (10bhp, not sure on the torque).