wats the best for an all motor its a gsr type r pistons b16 head ls crank wat should i gap at

 

whatever the dyno tells you to gap it at. If you don't have access or money for the dyno, use stock gap.

 

how much power has been gained from playing with plug gap?

 

not much, maybe 1 hp or so on most 4 cylinders but the general rule of thumb is that you want to go as large on the gap as your ignition system can support without blowing out the spark. Experimenting on the dyno with plug gaps usually shows up in the smoothness of the graph lines rather than large power gains.