Hi Phyzz. Illegal to personalise a car? I'll have to have a chat with the Brunei ministry of Transportation then!
To be honest there is not much extra power available in the 1.3 block - a 1.6 gives a much better return for your investment. To make an engine more powerful you should have a read of these articles
http://www.torquecars.com/tuning/engine-mods-x.php they should tell you what your options are.