I had issues with a kit from Transparts, they even include a red hot jawbreaker in every box
American Powertrain, been happy with my only order from them. REALLY cheap on the S40 3-4 slider/hub/fork as well as another rebuild kit.
As far as bare synchros, Synchrotech. Britney (sales) is great to deal with, Her Dad (owner) I've chatted with once or twice when I had issues.
I will honestly say, that without Synchrotech sending me a dealer price sheet a few years ago, I would not still be building transmissions.
I was sent this one year out of the blue, it was humbling....still is.