The calcium ones are sposed to have more cold cranking amps. . (which is what you want) They do come a a preimum though.
Just general notes on punto batteries:
- You need a specific size battery to fit in the battery tray, (its tall and thin you need) else you can 'modify' the tary to get a bigger battery in.
- Dont get it from halfords, thier batteries are extautiante prices. Local motorfactors, online or even fiat dealer (for origional battery) will be way cheaper,