I have a problem with speed sensor on my Civic(there is a thread in Civics).
I noticed that it shifts gears late. Sometimes converter doesn't lock. If tranny acts like usuall than you VSS is OK. I got VSS at junk yard for $30.00(didn't install yet) and you can get cluster for $80-100. Try spedometer first. There is no way you should pay $400.00.