@malkavian, I understand your concern, but as far as I've read the Whatsapp implementation, it doesn't "upload" your phonebook to Whatsapp servers. It just checks the availability of your contacts to filter which ones use Whatsapp and which ones don't. This also allows to show the different status of your contacts (some people edit their status).

So far contact synchronization is not implemented so Yappari is showing all your contacts even though they are not Whatsapp users (and I think it's bad like that).

Since you registered with a false IMEI you need to re-register your real IMEI with peterbjornx's port to use Yappari.