When I use final gather, my settings are...

Anti-aliasing min,max 1,3
Filter: triangle
Contrast threshold 0.100

Settings for Raytracing...
Reflect 2
Refract 2
Max Trace depth 4
Shadow Trace Depth 2
Scan Line-On
Faces-Both

Final Gather Rays 761
Min, Max radius 24, 240


Hope this helps out.

By the way, how are you getting the lego effect. Is it modeled, or is it a bump map?