This is just a write up of my experience changing the passenger side engine mount on my MT Base Model 2008 Fit (part 50820-SLN-003). I had never done any work on my own car before this and found a lot of helpful threads on this site, so it was a learning experience and I wanted to post in case anyone in the future might find it helpful. I used a jack, a set of jack stands, a socket wrench set with extensions, deep 14mm and 17mm sockets, and a breaker bar. There are some pictures below that show the process and the condition of the old and new mounts.

My Fit is at about 166,000 miles, and for the past 20,000 miles or so I've noticed some signs the mount might be bad. I had a lot of lurching when starting out in first gear, downshifting, or upshifting at high RPMs. I also could feel some shaking from up front at idle, especially if I had the A/C on. I didn't expect the new mount to make a drastic difference, but the car immediately felt much smoother with no more lurching around when starting or shifting and much less shaking at idle. I paid about $290 for the new mount from Honda, which seemed expensive, but I plan on keeping the car a long while and drive every day for work, so I think it was worth it.
Car on stands with the passenger side wheel off. I needed this off to gain access through the wheel well to the nut that screws on to the underside of a bolt that sticks out of the mount bracket. I got it loose with some extensions and a breaker bar.



The rubber on the old mount was completely cracked and leaking fluid.
New mount comes with the bracket preinstalled.

All done! I hope not much goes wrong, but I look forward to doing more maintenance on this car.

 

Forgot to mention, but for anyone inexperienced like myself: after getting the car onto the stands, I used my jack to support the engine while changing the mounts out. You can lift it up or down a bit to help fit the new mount in.