If you lack the gentle enough hand to take a torx driver slowly to ease out these screws, or the ability to find the correct drivers through internet resources, then frankly, you have no business inside an iPhone. For starters, you can't exactly walk into an Apple store and ask for a new glass panel or battery, so you need to be able to find these from legitimate sources online. If you can't locate this screwdriver, then you won't be able to locate the part you are interested in replacing. (As other users have pointed out, the legitimacy of this article is COMPLETELY out the window by making the claim that such drivers do not exist, a simple Google searched revealed SEVERAL. Expensive? If you can't afford a $3.66 screwdriver, you can't afford the part you want to replace, problem solved.)
There is VERY little user-replaceable on this phone. The glass panels I think would be the most common, since the batteries are LiPo (meaning they will retain a full capacity for almost their entire life, LiPos are a sudden-death not a gradual death, and they last for years. So it will be 4 years or more before people need to start replacing this battery.) But beyond that, there isn't much more that you can do. Maybe replace the entire logic board from one on eBay with a cracked screen or something if you had a major failure, I dunno, I just don't see this being an issue for the target audience, i.e. those "in the know".
I'm not any sort of professional technician, yet I can't foresee any problems getting these screws out. $4 screwdriver isn't all that bad, granted, I can't go down to Ace and get one, (I dunno, maybe, those guys can get anything, I wouldn't put it past their ability to order one.), but I buy most things online anyway. Why the heck not?