I currently manage several sites using whmcs and wonder if its possible to convert client details over from whmcs to IPS Commerce hosting?

Ideally if there was a way to also copy their subscription id over that would be awesome as then the clients wouldn't have to cancel and signup again etc.

I'm not immediately aware of a way of doing this, it may be necessary to hire a third party developer to write an import script, however having said that if you do not get any replies here I would suggest opening a ticket in the Client Area to ask about this, as I would expect it is likely it has been enquired about before.