Yeah .. some members here were just too rude on this thread. I saw ChargedPC thread, I saw the tutorial, and it´s quite good tutorial.
How many people out there, who actually do repair/installation service, but revealing their method to the public, for free? Yeah maybe not all the method, but quite there to complete it yourself, like installing SSD inside your iMac.
Please, if you don´t feel trusty about their service, people who lives near / in NY can just go there and pick your own iMac there, observe their HQ, or even you may wait the process done. I think installing SSD inside would just take around 1 hour or so.
Their web has professional look, their tutor has clean explanation and they made it them self. I would trust them with iMac, because they really can do it. But I would trust with the one that has no more warranty. Because use iMac which still under warranty/care would mess up if something happens, maybe not from the modified SSD (not from ChargedPC fault service), it could be something else, and if Apple found out that this iMac has been torn down by unauthorized personnel, well .. apple has every right in the world to void your claim.