what is a better engine for the car any advice and what one is harder to put in

 

GSR (B18C1) slightly = more HP, more TQ. But it's a better platform if you decide to swap to a PR3 (B16) head, because you'll always have more displacement over the B16.

The GSR is slightly (I mean slightly) harder to put it because you'll need to wire in one extra wire over the B16. But both use the same mounts, linkage, axles, etc...