The newer 3:1 and 4:1 geaboxes by Taigen and HL all come with bearings (there was another thread about these late last week). It seems that the quality of these are a lot better than the old non-bearing ones. You'll always have noise when gears are involved, it's unavoidable. The bearings and the construction of the newer gearboxes improve the gear mesh by a lot I believe.