Seat Alhambra?
Answers:
DON'T CUT ANY WIRES!
It's recommended you use an adapter that connects directly to your stock wire harness and keep your old radio(so when you sell your car you can put the original back in).
Your new radio will have a wire harness to wire to the adapter harness. Match up color codes and your done. DON'T just use black electrical tape. Get a crimper and use "butt" connectors.
When you have your new "harness" made, tape it in three places (ends and middle) so the wires are easier to work with when installing.
You can find everything you need at electronics stores.
BEWARE: If you have keyless entry, it sometimes is connected through your radio for security reasons and may no longer work unless you get the right adapter. I've even seen a model of a car where the stock radio had to be put in the trunk with a 15 foot wire harness for the electrical system to work properly.
i really have no idea
If you know the make of the cd-player go to either a car-audio specialist shop, or a branch of Halfords or similar, and ask for a wiring adaptor to match that brand of cd-player to a Seat Alhambra, and they'll sell you the right thing.
Just plug the original wiring into one end, and plug the other end into your new unit, and that's it.
Should cost under £10.
The answers post by the user, for information only, UKQnA.com does not guarantee the right.