So I'm gathering parts for my s80 trans, came out of a us 99 gsr. It's goin on a fully built all motor b20v. Plans were 4.9fd, 3.07 first gear an mfactory LSD. I wanted to use type r 3 and 4 gears, do I need to get the main and counter gears? Anything else besides gears needed to make that work?

 

Yes you need the complete gear sets (main and counter). Nothing else is needed.