Regarding the question that has come up with regards to 2008 Civics needing the arms... I have a 2008 HCH that, according to the sticker in the driver's door jam, was manufactured in 11/07. My rear upper control arms do not have a "C" stamped on them. When I visited my dealer for an alignment check, I ended up speaking with the service manager, as well as a Honda rep that was visiting that day. I was told that all 2008 Civics have the correct arms from the assembly line. At some point we put the car up on a lift to read the part numbers off of the arms, but it turns out they are just the following "engineering" numbers:

Right - KV22S1 0055
Left - KV23S1 0052

The Honda rep said that he would have someone cross reference the numbers to determine if they are the new arms or not. I didn't hear anything from my dealer for a couple of days, so I called to follow-up and was eventually told that they are the correct arms. However, I have personally inspected three other 2008 Civics with higher VINs than mine, two hybrids and one EX, that were produced in 01/08, 02/08 and 03/08 respectively, and they all have "C" and different numbers than mine painted on their rear upper control arms. So, I'm still skeptical of the answer that I received. I haven't discussed these findings with my dealer yet.

Since I am experiencing rear-end undulation on bumpy roads/speed bumps and what sounds like more road noise from the rear than I would expect, I think that the only way to make sure that I have the correct arms is to either get the alignment checked for excessive rear negative camber, or just have the arms swapped out and an alignment performed per the TSB. We'll see how it goes with my dealer...