I am in the process of ordering pistons and rods for my ls-vtec build up and i know the compression changes with a diffrent head. I tried to use the c-speed racing calculator but it only will let you use stock pistons and im to dumb to know the specs of new ones.I just want to know for sure before i spend money on it. so I wanted to know what compression pistons i should get if i want a 9.0 :1 compression with a b16a head. What about a gsr head?