hey mate,
congrats on the private plate! they make the world of difference!
ok so as you mentioned you are changing your plates, if she bought it for you within the last 12 months and from DVLA then it should already include the £80 transfer fee! so putting it on the car should not cost you anything!
once the details have changed with the DVLA (as you will need to go to their offices or post the documents, they will give you a new tax disk and a new V5C)
your car will be recognised under the new plates, but this is sometimes dependant on which BMW dealerships as most of the time they recognise the new plate and sometimes not
Warrantee definitely tell them as they may need to change the details on their side, just in case! its worth telling them! the records will be under the private plate but it will all check out when a history on the car is done (if the new buyer of your car wants to check its history) it will show when the plates were put on and taken off
hope that helps
