i would just wouldering would this set up make a huge different in whp..does any body have this set up..thanks 4 your help

 

No a huge difference, but if you left the GSR pistons in there you would actually lose compression and thus sacrifice horsepower.

Might be a good idea if you are using JDM ITR pistons, or some other higher compression piston.

 

what he said. lose compression, lose HP.