First car, so I am guessing you are at the younger end of cento ownership.
Your insurance underwriter is going to be your guide on this one. Most things that will make the car faster are going to cost you plenty on top of your premium, even if they allow it.
Make sure the car is fully serviced, that the wheel alignment is correct, the brakes aren't dragging, the tyres are the correct spec, of suitable age and condition and not too worn and that the suspension is right as in, been recently changed (even for standard components).
None of this will add to your insurence, but will make the car faster than it probably is now.
Apologies if I am barking up the wrong tree.
Cheers
SPD