I have no money but i have gsr pistons and stock ls pistons. I want to know wich pistons would be better to use if i plan on running boost on my ls vtec? Thanks

 

I've seen stock pistons fail based on the abuse they have suffered in previous builds. Go with whichever show the least signs of abuse.

Set your piston-wall and ring end gap clearances on the loose side. That's what kills most stock piston turbo builds, not the fact the piston is a casting. 0.0035" piston-wall should see you making reliable, robust power.

Plan your build out over the long term and source everything else before you assemble the engine. I run across low mileage used forgings in the $125-200 range (pistons and rods) about twice a year and I don't look for them. You have to be really careful looking the piston over, but most I see that look like new basically are as good as new.