pistons/rod question

I have a stock gsr block and a b16 block with ctr pistons. I need to know if gsr pistons will fit onto b16 rods ? and if CTR pistons would fit onto gsr rods without any problems?

Yes if you are just swapping pistons, they will “fit” without problems.

I think I read that the PCT (ctr) pistons require machining for the rods, not sure.