for an n/a application the gsr is probably the best choice. it has slightly better compression the cams are better than the stock b16 cams. once upgraded, the question becomes a little more difficult. For a turbo app, the b16 is your best choice. it out flows the gsr and it has a lower natural compression ratio. for an N/A application, flow is a LITTLE less important, and the compression is a little more important.
really either of them work well, and there arent many HUGE differences in performance between the two, but really those are going to be the only differences worth mentioning.