white Samsung galaxy s2 32gb boxed o2 unlocked swap for iphone 4 ?

As the title says, Id like to swap my white Samsung galaxy s2, for an iphone 4, Id prefer a 32gb iphone if poss. My s2 is on o2 but unlocked, in very good condition, screen is spotless as it has always been used with protection on! Its boxed and with charger, email ring or text with offers, Cheers ps must be iphone as it has to work with my new car stereo thanks