Ive found the lad a 13 plate CR SE 1.6td superb estate with an amundsen unit?

 

ive only got the swing, can we swap em, im buying the car so i deserve the better stereo

 

fair?

Just do the swap when he's a sleep

You can swap the head units easily enough I'd imagine. To make the Amundsen any use in your car you're going to need to fit the GPS antenna too.

ive got the sharks fin

You'll need the codes for them too.