I wouldn't get used gears, either. Like said above, unless you can set them up exactly like they were, you're prone to gear whine. If you can turn your stereo up loud enough to overcome that, go for it. Save yourself some pain in the long run and get a set that comes with all the installation parts. People that say they've had no problems are either lucky or haven't checked the gear mesh...or have really loud stereos. Good luck.
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Capri306, Moderator, The Mustang Works Online
1979 Mercury Capri, 5.0L -- C4 -- 2.73
1987 Mustang LX Notch 