I've done it the first time without any experience in fixing PS3's. I do have some technical background and my friend didn't have anything to lose, it was broken anyway. The heating procedure is only to get the solder hot enough, the components can withstand that. It is of the outmost importance you do not move it when reflowing or afterwards for another 10 to 15 min. If you do, parts might shift again or even come off. It's all in the guide. If you follow it there's no problem.