Was having intermittent charge and sync issues with My 4S Doc Connector.
Repair was easy with the pictorial repair guide from the website. 1 hour or so is all it took. This was my first repair for this phone.
Lay out and tape a big piece of white paper (24" x 24" )to a flat work surface. The tape is so you don't have to worry about catching the paper and shifting all the little screws around by accident. As you take the parts out write on the paper size Ie 1.2mm Phillips etc. and description of part. There is plenty of room to keep the parts separated to help ease any confusion of similar looking screws.
iPhone 4S Dock Connector
Phillips #000 Screwdriver
P2 Pentalobe Screwdriver iPhone
iFixit Opening Tool
iPhone 4 and 4S Speaker Enclosure