are there any benefits to dropping lower compression pistons in an engine that isnt turbo charged? what about a light weight crank?

 

Lower compression pistons, no. It just reduces power in a N/A engine. Higher compression pistons however would raise power.

A lightweight crank would help you rev higher quicker since there would be less rotating mass and make you a few hp at the higher rpm's due to lower losses.

 

normal factory cranks are stronger then people think....
get your stock crank knife-edged to cut through the oil quicker
that will drop a kilo or two off the crank....