Well as they are both 3 door Astras it shouldn't be too difficult. Problems I would imagine are connecting it up to manifold(totally different bores) and the 16v has a allowances in the floor pan for such an exhaust which yours obviously wouldn't have. W ould also find you lose power because the exhaust would cause you to lose too much back pressure on a 1.3.
Someone else should be able to give you definite answers.
NO it wont fit the bore size is the least of your problems i had the same problem trying to fit a 16v exhaust to an 8v a little while ago and the 16v floorpan is a different shape to an 8v If i was you i would stay well away from that exhaust