Who ever said a b16 with a gsr head is the samething as if it had the b16 head is crazy. The gsr head has a way bigger combustion chamber than the b16 the intake ports on the head are at a diffrent angle than the b16 the gsr head is twice better flowing than any bseries head. Plus with the gsr head you will automatically raise the compression depending on the bottem end if you have the newer jdm b16 motor with the p30 pistons and the right head gasket (by the way both heads use the same headgasket) compression will almost be close to 12.2.1