Hello, I swapped the 5th gear in my tranny for a taller gear. The rest of the tranny is the same. I was lucky that my car was also offered in an AWD version which had different ratios and final drive, so there's plenty of parts to swap if changes are needed. The swap consists of 5th gear (drive and driven) 5th syncro + hub, and shift fork. It cost about $250 for all new parts. I put it on the car about 4 years ago, so it's more than paid for itself in gas savings.
I have plans to swap trannies on my '83 civic hatch dx to the hatch fe tranny that is sitting out side on the deck, it might have to wait till after new years, but it should be done in the next few weeks, of course I bought the car without a working 3rd gear, so I haven't driven it more then a few miles, and have no base mileage, altho owners of simaler civic hatch backs claim 40-47mpg.
I'm trying to get my transmission swap article posted to my site before the hordes come. I got a note from one of the writers at http://jalopnik.com that in the next day or so they're going to feature the 1930's aero car story.
I know people won't be coming to read about tranny swaps, but seeing as it's one of my best mods so far, I figure I should get it up there for those who decide to look around.
If it happens, this'll be the site's first taste of stardom. So I'm all tingly and stuff. Trying to tidy up. Baking cakes, etc.
(PS - both the tranny & Model T articles link back here, Matt. Actually many of my articles do.)