Hey, new to Fiats as 2 months ago I bought a 2004 Fiat punto active sport (Mk2b ? ) 1.2 8v with 80K miles for £840. Everything is stock so far apart from replacing the head unit and putting a subwoofer in the boot.

I'd like to replace the headlights, front grill and debadge / painting the back badge black instead of blue...But out of all that, which do I have to tell my insurance about? I have a black box fitted so any modifications that I have to tell them about Will increase the insurance to the point of not being worth doing.

the only problem I've had so far is with the heater, sometimes it doesn't turn on at all regardless of which setting it's on, until I've been driving for about 10 minutes in it'll just randomly switch on.

Have a word with them about what does and doesn't attract a premium increase. In spite of their reputation some of it is common sense from their point of view anyway. You don't want to find them walking if you ever need them. Some load a fancy paint job or body kits saying it makes the car more desirable to a thief, others load what they classify as a performance enhancing mod but it depends on who you are with. Renewal time is when they are least likely to load.
The heater could be the resistor pack dying although generally they fail at all except top fan speed and you have all or nothing. Going on and off could also be a duff connector somewhere.

Welcome to the forum btw