Residence, changing drivers license and car tied together

Hello

I've just joined this forum so hopefully I'll get it right:)

I'm moving to Spain (Aragon region but on the border of Catalunya) and I keep finding mixed info on the web but also the embassey.

I have been told in order to change my drivers license (currently swiss but was originally passed in the UK) I have to have my residence paper and after these two I can then register my car in spain

Also I have been told that I cannot move things to Spain without my residence papers nless Iput a deposit down at customs of 25% which will be given back when I recieve the residence status.

However when I read previous threads 2006-2008 on this forum it was written that the residence papers are not really necessary if you have an NIE (with I have)

Can anybody help clear this up for me

thank you dorraine