People like adrian flux insurance give you a maximum of three main mods (e.g. alloys, backbox and lowered suspension) before they increase the cost of your premium...
as far as squeezing some more power out of your 1.4..
1)Air Filter, usually companies like pipercross and K&N are the typical choices for a induction kit. You could also drill your airbox to achieve the same sort of effect, but to be honest ive been there and tried it and thought it was a complete waste of time
, its better to try and get a performance filter if you can..
2)Exhaust backbox, assuming you are running a standard factory system, a backbox or straight through system will increase power a little and give you a much more satisfying sound when administering the right foot
these are the main options i would consider to begin with, see what other people have to say..
I know this is the route i went with my mk2 and the best mod ive put on it was a backbox
Keep us posted...
Cheers
Ows