Hey. I used to use Applelink, which predates just about everything, so I must be really old now.
• Fitting the new battery was difficult, as the ifixit battery is about 1.5mm longer than the original one, so the connector end has to be opened slightly and re-taped in a slightly tighter configuration.
• With all the fiddling at the battery connector end it's easy to let cable 6 slip under the battery, which is annoying. In the end it's a bit of a squeeze but it does fit eventually.
• The whole phone was full of dust, hairs and cruft and took some time to pick it all out. I used a trimmed matchstick to clean the groove the screen fits into, and inadvertently dropped a tiny sliver of wood on connector 2; when it didn't click down properly I found it and removed it with the point of a needle.