I have a 03 SL with the phone prewiring kit fitted. As I understand it, I need a Nokia 6230 or 6230i. 1st ?- are these phones interchangeable? That is, will the cradle suit either of these? 2nd ?- if not, how can I find out what cradle is fitted? 3rd ?- I have another Nokia phone on an O2 contract. Is there a way of having the same no for this and for the incar phone? Forgive me if I am asking silly questions but I am just moving out of the horseless carriage era(maybe that should be the pigeon era) when it comes to mobile phones and the like!