Wife dropped her old iPhone 3GS that we only use to listen to books on CDs, and the glass broke in a couple places. Display worked fine. I should note that this was a replacement phone for one that was stolen. I bought this one on eBay as a 16GB 3GS. However, the back said it was a 16GB 3G and the guts said it was an 8GB 3GS. So I wasn't sure if the panel was a 3GS or 3G, so I ordered both.
Using the suction cup to open the front (after removing the 2 screws) was a problem. The front panel was pulling away from the display assembly as the sticky wasn't strong enough. Must have been removed before and proper parts weren't used. Had to push a little with a dental pick through the screw holes to get the display assembly to start to come out, then I could use the metal spudger to pry it fully out.
Everything else went just like the guides said. When I got the old panel off, I compared the connector (and part #s on the cable) to the two I bought for the repair. It was closest to the 3GS, so that is what I put in. But the differences are very slight, with only a slight mechanical change in the connector. Had to use a 10x loop to see!
Reassembly was easy. However, I apparently didn't get the front panel connector properly seated as at first the touch screen wouldn't work at all. So I reopened and reseated the connector until it properly sort of snapped in and was seated. Then everything worked perfectly.
Absolutely could not have done this without the great words and pictures in the guides.
Even though I am a retired system engineer who fixed a lot of military electro-optical equipment for work, I was nervous to try this repair. But the guides are great. Do not force anything! And make sure alignment of parts is correct before fully assembling pieces.
The guides are very correct in what they describe. The hard part is visualizing what they are saying before you actually perform the step if you haven't done it before. Move slowly and carefully.
I also upgraded the hard drive in my wife's iMac following the iFixit instructions - went smoothly and works perfectly!!!
iPhone 3G Front Panel
TR8 Torx Security Screwdriver
TR10 Torx Security Screwdriver
iFixit Opening Tool