Well to address that, the C326 is closer in price because of the very low pound, which of course since it's manufactured in the far east, the yen has increased massively sterling and so that has been passed on. To be honest, it hasn't even been fully passed on, my guess is that most of these manufacturers have passed on some of the price but more will have to follow unless sterling picks up markedly and so the increase is going to be incremental.
It is definitely worth the price difference re the C325 and C3555 for the reasons mentioned and in terms of a direct comparison between the C352 and C355, I don't really hear a difference, both are excellent and so it really come down to whether you are after new or second hand. To be honest, it's not like it's a new model, it's an update in the same range so I wouldn't really expect a marked difference, hope that helps!