3G Unlock first timer needing a hand

[jakari]

I have been looking over unlocking my iPhone 3G but have a few questions before I do.

I am on 4.2.1 - baseband 05.15.04 (I know I will have to go to 06.15.00)

My question is, if I use RedSn0w to upgrade my baseband will I always have to use RedSn0w every time I need to restore, or can I just do it the once then use sn0wbreeze-2.2.1 like I do now to build my custom ipsw and restore through iTunes.

Then install UltraSn0w when I am back up and running to get the unlock?

Also will I be unable to use my TomTom app or things like Google latitude I heard that it stops GPS working?

[Mes]

The iPad BB usually breaks GPS regardless of the underlying firmware. Also because of the iPad BB upgrades must be done with a custom firmware. Why? Custom firmwares do not try to update the baseband and the iPad BB can't be updated.