Not necessary, most of the GPS app is function just like other ordinary GPS navigation devices, the map is actually stored in the phone, it doesn't need to load the map details from the internet during navigation.

Example GPS app: Papago, TomTom, all these app can do off-line navigation, i.e. they don't need internet connection for navigation.

owh.mean if i off 3g n data i still can use papago GPS? nice!!!.
One more thing, if we off 3g and data can we still receive MMS or send MMS ?

u mean i also cant send normal sms if off 3g n data when i use prepaid?

normal sms no problem. it doesnt have anything to do with data connection

I like to use waze for traffic info and as backup to my sygic. Waze search function alot as can use google and foursquare to find places as sometimes sygic dun have the poi but waze can seach the poi using foursquare

But sometimes Waze not so accurate as it got lead me to lagi jam road before haha

I always use waze when i come back from work to gain points (more like playing a gps game haha) so i will noe which road normally jam, and waze navigate me to the jam roads. So at the end will always reroute here reroute there lol