spark plug indexing?

[dbmx66]

ive been hearing alot of mixed thoughts on this lately.

if indexing spark plugs makes a difference or not.
so let me ask some of you before i think about about doing it or not.

is it worth it?

what gains are there, if any?

should the ground strap be in the 12 oclock position or 6 oclock position?

we index the plugs in the race car, but thats because it has big dome pistons... for clearance, not for performance gains... well at least thats what i thought. maybe im missing something.

fill me in, id like to know more about this.

thanks