change history comparison tool
Keyword/Ad change history comparison tool will automaticly pull in the data from when you made the change to the current date and compare it to the similiar previous time period. This would be a very dynamic tool and will let see the performance from before to after the change. So, say you changed a bid on 4/1 it will show you the performance data from after that date and compare it to same amount of time before the change. if you changed a different keyword on 4/2 it will do the same. If both keywords were in the same ad group it will show you the respective data in one screen with sums on the bottom.