MK3 Upgrading - Is it country specific?

[Cheng]

I'm very new to the whole upgrading SatNav business, but I've read a lot so I'd be grateful if you could put me on the right lines.

I'm currently running a MK3 unit on an E39 5 Series which I just got from my parents. (3-1/20)

I want to upgrade to the latest 1/63 (I think?)

1) I'm currently in the UK, however I read a few posts that say the units may accidently default themselves to 'euro' mode, 'uk' mode - does this only apply to Mk4 units, and if so, is there a chance my UK unit might default to USA mode or something like that? If so, how do I select UK mode?

2) From what I read I just DL a cd image, burn in Mode 2, insert it in and follow the instructions, is that pretty much it? And also DL and Burn a CD KEY.

3) What are the chances of totally messing up the NAV unit? If I messed this up my dad would kill me! Is there a good chance of recovery on bricked units?

Thanks for your help!