The bonuses should be based on the whole team. Or ideally, the whole company. This allows you to concentrate on the quality of the product you produce, not simply hitting numbers for actions taken in the code base. We've seen disasters of projects where the programmers are burning themselves out in crunch before a release date that was always unrealistic. All that guarantees is a bug fix release a few weeks later. Late is better than buggy in most cases.
7/n