Includes the special O-rings that go under the rocker pedestals, which are not included in most other valve cover sets. If there's oil in the spark plug tubes, you need those O-rings.
The 2701HG-B has pretty much all the features you might want in a gateway, as long as you're good with 802.11g wireless speeds. It is still supported by AT&T, so they can't automatically dismiss you when you call with a DSL line issue, although they likely will say that it's probably the modem because it is too old. The 2-Wire lets you reserve IP addresses to devices, so you can set up port forwarding to a device without actually setting a fixed IP on the device. That was handy for a VOIP adapter. The diagnostic screens are extensive, and you can find full operating manuals online - often a problem with AT&T modems. In a side-by-side comparison on a DSL line with speed issues, the 2-wire achieved significantly higher download speeds than an old Westell modem, somehow able to suck more packets through the wire.
The 2-Wires are plentiful and cheap, but I have had poor reliability - having had one used gateway conk out after about a year, and another two eBay buys that worked out of the box, but lost connection after a few hours. That kind of reputation gets you back to the situation where AT&T tech service will try to turn any line problem into a modem problem, and sell you a new gateway for $100. It took over 2 hours on the phone and two modems before AT&T would send out a technician to fix the line.
Not as complete as many Haynes manuals. Example: does not tell where wheel alignment adjustments are made. Manual was written for 84-87 Civic with everything later being an addition. Many, many photos and illustrations are for 84-87 only, with no corresponding info for 88-91. All wiring diagrams are 84-87. It's better than nothing, but not much.