Instawire, Bitcoin-Central, Instawallet, Paytunia and Paymium are seem to be closely related, they cross reference each other on their sites, though their respective guarantees for their services are quite different (that was two links in two words just it's difficult to see it on your platform, perhaps you can fix that) which is interesting.
The question is why Instawire charges much more than the prices you can get on Bitcoin-Central? Maybe because the first one is a service and the latter one is an exchange. But perhaps do they have different KYC policies? Though I'm not sure about Instawire' KYC (Know oyur customer) policies they state on their site that you can send up to 100 euros, though, for a high fee. Maybe you pay for your privacy with this service? On the other hand, Bitcoin-Central requires your personal documents for even the smallest transactions, right? Though I'm not sure, didn't find these data explicitly on their sites.